In many arguments I am a part of or even witness, I notice a lot of people involved will use emotion as an argument rather than facts. Before anyone starts calling others out for it, it is both sides not one or the other. 

For me, whenever anyone uses emotion as an argument, they practically admit they can't argue their point effectively or simply don't have anything to say about it.

Please note: Emotion in an argument is:
Swearing/insults
"Think of how you would feel if ____" 
Anything like that.

Now, my question is purely... Why? What benefit does it have? Why is it used?

Heat of the moment, people's 'sense' become lost and emotions start flaring. I may or may not have been on the recieving or delivering end of it. 

Axis, maybe you're missing the point because it's so big and obvious.

The human range of emotions affects everything we do and say. Emotion drives our actions as much or more so than hunger, thirst, or other physical needs. Think of how people are impacted by laws associated with the emotional response to things:

You can't shout "FIRE!" in a crowded theater because people will experience fear and then run and panic and hurt each other via trampling.

Communicating threats via Twitter, for example, is not allowed because it causes people to feel that same emotion, fear, and then they behave erratically and potentially in a threatening manner.

Bullying elicits emotions. People say things online that make others feel bad about themselves. I have read so many articles where someone commits suicide because they get made fun of on Facebook or whatever social media platform. To me, you just hit the big X in the right side of the website and you don't deal with it any more. But emotionally charged conversations about bullying, or firearm ownership, or religion, or sexual orientation lead to legislation.

Why do people do it? Because emotions are a legitimate experience we have as human beings and it is a part of the existence of being us. To say everything is cold or clinical is wrong.

Just because emotions are legitimate experiences does not mean they're legitimate forms of arguments. 

Example: Let's take the school shooting in San Bernardino, California today.

"How would you feel if your child was in there!? We should ban guns!" - That is not a legitimate argument for banning guns, but it happens all the time whenever it happens. They will stand on the graves of those killed and use that as some sort of argument for the banning of guns. It's not an argument, it's a cowardly act in an attempt to gain an emotional victory, because they can't win in an out right debate.

You just answered your own question. Why would someone use facts and legitimate arguments when they can win people over by simply appealing to their emotions? You could always use both legitimate and fallacious arguments. 
Appealing to emotions happens on both sides of arguments. Your example is just more common and recognizable.

Emotional appeal is the last straw for people who don't have any real or valid reason to whatever idea they are trying to defend or promote. Why use facts, or actual real life examples, when you can make up an imaginary scenario where some poor person might have their feelings hurt--or worse. It is pretty much a surefire sign that someone has no actual ammo left in their argument.

CTP Axis:
earthwarrior :
A user of this :

I used to try every way in the world to crush as much of my emotion as possible because I saw it as an undesirable natural human flaw that gets in the way of logic. I was wrong.

Logic isn't flawless. A logical deduction, as far as I see it, is basically the same thing as basic math. 2+2=4, but in anything outside of numbers, there are varying assumptions or beliefs as to what 2 and 4 represent. Any deduction can be logical, regardless of how correct or incorrect the information used or the result is. Let's use Axis' example once more, but from the opposite side of the argument.

"How you YOU feel if your child was at that school? There should have been more armed security or even teachers with guns to protect them."

This is the very same appeal to emotion, and not necessarily fear mongering, either. If anything, it's a projection of how you feel about the topic. People argue their point of view so adamantly because they have core beliefs. So why do you believe what you do? If you say "because it's logical", you're right, but only because logic is based on beliefs. What you have faith in doesn't change the fact that faith is faith.

So let's go over it one more time. Faith and beliefs are emotional. Strictly subjectively speaking, everything in your head is defined by what you believe them to be. That means that all logic is both emotional and subjectively correct, regardless of misinformation. And if logic is based on emotional beliefs, every argument is an emotional argument.

m0ssb3rg935 : Here's a fun fact to back up your whole point and your discussion.

2 cups of salt + 2 cups of water does not = 4 cups of salt water.

That is all. Carry on.

Ghostbear1111 : Disclaimer: this is going to turn into a pretty ridiculous semantic discussion.

It really depends on how it's distributed and how "salt water" and "cups" are defined. At that point, it's gonna be a really nasty, gritty slurry, but one that consists of only salt and water. So technically salt water. If distributed as a half-cup of salt per half-cup of water in four measurements, then technically four cups of salt water.

I think I might've lost my point somewhere in the middle of all that, though. I guess what I really mean to do is agree with you in saying that emotion is present in everything, including rational arguments and that they're not something that can be independent of each other, and also that they're not always invalid.

m0ssb3rg935 : While that's true; when an emotional argument is being used, they aren't talking about their faith, or asking about yours. While there's emotion and logic go hand in hand, your point begins to fall apart as soon as one takes over the other.

Even though I am well-reasoned on paper, speaking is much harder since it's instantaneous. I usually have a lot of time to think about my argument on paper, whereas speech is instant and requires quick thinking.

With time, I've come up with a catch phrase to test people's opinion: According to what objective standard? Whenever they claim something I disagree with, I come back with that sentence to understand why they hold that point of view. More often than not, even when asked calmly, they usually can't provide a solid argument in defense of their opinion.

I'm a pretty firm believer that there's a big difference between an argument and a debate. During an argument, you believe that your point of view is correct, that the other person's point of view is wrong, and you attempt to convince the person to change their perspective. I'm not a big fan of this method, as it's usually very emotional and rarely ends in a positive resolution.

A debate, however, is generally known for believing your point of view is correct, believing that the other person is incorrect (same as an argument so far), but then explaining your position and how you landed on your perspective rather than convincing the other person that they're wrong. This is my preferred method, as I believe strongly that the best way to change someone's mind is to let them change their own mind.

As an example, religion is a hot topic. Let's say that you're Atheist, and I'm Christian (most common religions in America). If you ask me why I'm a Christian, and I say something like the following, you're not going to want to listen... right?

"I just don't understand how you could be Atheist! It's absolutely stupid to look at the world and think that it's random, there's no way it could happen by chance! Use your brain, you're wrong on this!"

Again, there's no way you have a positive response to that message. You're instantly going to be defensive, and you're going to pretty much ignore what I'm saying because of how I'm saying it. I could also be more subtle, yet still elicit an emotional response...

"I'm so so thankful and happy that I'm a Christian! God's handiwork is evident, and creation shows that He's real! Thank you, God, for revealing yourself to me!"

If you're coming from a perspective that believes that there is no God, this is going to probably annoy you more than anything. You likely wouldn't have a problem with my first sentence, responding with 'eh, I disagree, but whatever'. The second sentence is where you might get a little touchy, as I'm claiming God is evident and that simply being outside would prove that He's real. The unsaid message there is that 'since it's evident, anyone who doesn't see God's handiwork in the world is somehow incompetent or blind or something'. It also says 'creation', which you might have a problem with, as the basis of Atheism is that there is no God to have created the earth in the first place. The third sentence could be taken as exclusion, though the speaker could claim it's a harmless message of gratitude.

Now, I don't want you to think it's wrong to say the second statement. We're talking in the context of arguments here (as opposed to a debate), meaning that everything said will be taken differently than if you're talking on your own (or around like-minded people. Please don't think I'm saying these are always wrong, but if it's already an emotional conversation or whatnot then something like this could fuel the fire.

A better alternative might be...

"I'm a Christian, because I believe that the Bible has been proven legitimate because [insert why]. I believe that the Bible is accurate, and this is because [insert personalized explanation here, complete with examples and such]."

This is better, because I'm very clearly talking from my perspective. I explain what the basis of my belief is (I didn't elaborate in the example, because this is different by person), and how I came to that conclusion. Again, saying 'I believe that [blank] because of [bank]' will generally not elicit emotion (unless the other person is desiring an emotional interaction).

All this to say, it's crucial to be as personal and specific as possible, while still clarifying that you're speaking from your own perspective. If you generalize, or speak from the perspective of 'you're wrong', you'll nearly always have a bad exchange.

(pls don't turn this into a religious debate, there's enough of those on the board as it is. I'd have written out examples from the Atheist's perspective as well, but I'm at work, and just don't have the time right now)