I had similar qualms, but after seeing the actual effects I've changed my mind, at least as regards Sommerles (I'm less positive to other forms of gamification, especially if they're considered an alternative to non-gamified learning instead of a minor supplement in a well-rounded system). We already have prizes and competitions and these external structures for sports and such. People send little kids into soccer tournaments, we just make sure the rules aren't too strictly enforced and the major part of the reward is for just playing.

I have a kid who loves listening to stories but isn't at all motivated to read alone – and probably would not have read a single book alone this summer if it wasn't for Sommerles. Maybe it's not motivating for all kids, but I'm sure happy it's helping my kid get some much-needed reading practice. I also think you underestimate children. My other kid, already a self-motivated reader, re-read short books really fast to get all possible prizes within the first week (librarian eyebrows were raised). Who was doing the manipulation here? :-)