I was next to this guy at a concert who was air drumming through the whole first band. He was cute, so at the break I asked him if he was a drummer. He said that he considers himself one, but he's only ever played rockband drums. I didn't even have a response to that.
At least when it comes to coordination and timing, rock band drums CAN actually translate to real drums (unlike guitar). Granted, if you're playing a drum set like you're playing rock band drums, ur doin' it wrong, but it actually is good for timing and coordination, but when it comes to feel, dynamics, and groove, that obviously doesn't translate.