I used to think it wasn't nefarious unless your gameplay mechanics essentially coerce you to pay for in-game currency to progress or otherwise fully enjoy the game. But it seems like it's enough just to sell cosmetic enhancements, because kids will be just as caught up in that as they would be in actual gameplay progression.

All that said. It's your kid, your card and your money. Kids a mischievous, but the blame isn't entirely on games companies.