I only started playing Rock Band because I didn't want to pay for drum lessons or buy a real kit because of costs, I figured that if I could get used to the foot pedal work and improve my stamina by going to the gym and playing Rock Band at home I could move onto real drums after a while if I really enjoy it.
It's helping but to be honest my coordination with my foot is awful, improving but still, it is way harder than it looks.
Well actually it's not the only reason I started playing, some friends play it too and we go to local bar nights where they have the game out for fun and get free shots if playing as a band. Always a laugh when there's 4 people playing at once.
I figured it would be nice to have my own kit at home to get some practice in on, hopefully in a few months I'll be playing the game on expert to a good standard and maybe in a year I'll get a real drum set.