Since about 2002, some Arcade games came with support for a Pass, which is used for the games. Basically, a player takes out a Pass, puts in on a Scanner that is located somewhere on the Cabinet, and maybe enter 4-digit Password. Using this Pass, players can store their High Scores, and in some games, you can have access to more content, and you can even unlock more. It's basically a card containing a gaming profile.

There are several types of Arcade Passes. The most common ones are eAMUSEMENT, NESiCA x LiVE & AiME.
eAMUSEMENT has been used by several konami cabinets since 2002. Some of the games that support eAMUSEMENT include:
Beatmania IIDX (After 8th Style)
Pop'n Music (after 8)
Most Quiz Magic Academy games
jubeat
REFLEC BEAT
SOUND VOLTEX
BeatStream
MÚSECA
Otomedius
DDR (After Extreme)
GUITARFREAKS & drummania (After 9thMIX & 8thMIX, respectively)

There is also NESiCA x LiVE, which is used for Taito games. Groove Coaster & the newer BlazBlue games used it for storing player data & unlocks, too.

Finally, there is AiME, which is used by Capcom & SEGA. Some games that support it include CHUNITHM & cross beats REV.

With one of these passes, it's also possible to participate in Events that are held in the Arcade games. From time to time, an Event will begin, and in that event, a lot can happen, like the ability to unlock more content by completing missions, teaming up with other players for a specific goal, or crossovers that bring content from some games into other games, like a Character from one game becoming playable in another game.

I'm getting quite curious: Is it possible to emulate these Passes that Arcade games use? What this means is: If someone has enough Viz, it can be spent on an eAMUSEMENT, NESiCA, AiME or another Pass to store data and unlocks.

Unless MAME adds such a feature, I don't think there is a way to integrate it ourselves.