Yup your right, I was just getting excited when I watch all these vids of people running multiple emulators.
I've seen some of those videos and, while the setups are definitely pretty slick, I'd be willing to bet that the amount of time those guys spend actually playing console games on their cabinets in 1 year amounts to a tiny fraction of the time they spent setting it all up with the fancy screen shots, animations, etc. If the stuff gets used and enjoyed regularly then fine, but if not, the whole undertaking seems extremely backwards and silly, IMO.
I eventually did add MESS to MaLa to run some console games on my cabinet, but it's a very no-frills, utilitarian setup that took me about an hour to get up and running. About the only time I ever use the console stuff is when one of my buddies comes over and we want to play some shoulder-to-shoulder NES Ice Hockey (which, admittedly, is pretty fun). To me, there just isn't much in the console world that's worth the trouble of setting up on an arcade cabinet. If the game has an arcade version, I'm invariably going to prefer that version and play it exclusively. If the game is a platformer like Megaman or Mario, then arcade controls just don't feel right. If the game is an RPG or adventure type affair, why would I want to play that standing in front of an upright cabinet? You get the idea.