Up until recently I'd have been highly supportive of this. A few days ago I read a counter argument, specifically to the gamification of education, which made the point that a) when you have extrinsic motivators, people are less likely to care about the things for instrinsic reasons, b) people tend to game the system rather than actually accomplish the thing you intended.

Dan Pink discusses some of the research regarding this problem in an RSA Animate video. (He also wrote a book about it.)