You mean like many fast food joints (Sbarro, Boston Chicken, Etc.)? The problem with that style is really in keeping the food up to quality. Unless you have constant, steady, turnover, you really have a lot of food just sitting around. For somethings this is not a problem, but for many dishes they get dry or start to go limp.

It's quite popular in many cities for lunch spots, I would dare say in fact most lunch restaurants are like that. Less so for dinner, where people like to sit down. on the other hand, I think a lot of stuff is prepared like that behind the scenes anyways.