Although substitutions work in some circumstances, like substituting butter for margarine in baking, or typed reports for hand-written ones, I feel substituting simulated "exergames" for organized sports or that guitar-to-the-rescue thing for learning to play a real instrument do not (work.) You can't become a professional rainbow button pusher and you can't make it to the big leagues or learn team spirit from your basement... no matter how many points you earn.
Even though they are fun, do you agree that video games can take value away from traditional forms of activities? That being said, are they better than nothing at all?