As a Music Educator I can see both sides.
On one hand there is a benefit to exposing music to some that would never hear it. I'm certain none of my middle school students would ever listen to the Dead Kennedy's except for Guitar Hero.
On the other hand some people take the game a bit to the extreme. When you're bragging about how you played Through The Fire and Flames on Expert with 95% rating I'm not impressed, rather I'm saddened. I'm sad that the person would find this to be something to be proud of.
If it can be taken as a way to be exposed to new music and maybe develop an apprec