Not sure which apple store your at but here in Canada only time it's busy is at a product launch.
That's definitely not the norm. There's three Apple Stores reasonably close to me here in Michigan, and they're all packed, all the time. It doesn't matter how near or far it is from a product release, they're always busy. The Geniuses are always busy, too, not standing around doing nothing. Appointments are there to try to keep things moving along. With as many people as the GB deals with in a day, if there weren't appointments it would be even more of a madhouse than it is, and there would be a lot more frustrated, pissed off customers.