For the same reason some real musicians spend lots of time playing Guitar Hero or Rock Band and like it.

A video game of an activity is NOT the same as the activity it's based on.

bah that's nothing...
In Quebec City there is this small place called "L'Intuition"... they have 25 different kind of poutine which are served with any of 5 different sauce... you can count yourself how many poutine variety that makes ;)