I cant see myself using it tbh. As has been said, you need to target groups of people that cant play together any other way for it to work. So yeah, young-ish kids playing football games on the Xbox, groups of 4 that want to play C&C against each other but can't move their PCs around, etc.
It would also have to be pretty cheap to be attractive, and considing how expensive 20 gaming machines is going to be (and the fact you'd have to upgrade them all every year) I'm not sure how you can make enough money.
One thing that did work - in Leicester, back when I was in 6th form there was a grotty cafe in town that we used to have lunch in. It was an awful cafe, bad food, dirty etc, but it was cheap and (more important) they had an n64 with 4 controllers you could play on for free. We went to that place all the time, and probably spent way more on food (£3 each a time for a tea and a sandwich?) than we would have been happy if they charged us for playing the games. I'd forgotten all about that place till now.