As you well know, the entire point of crypto is decentralization. Ownership of the games must be decentralized in a provable way. In this case, the puzzle-makers provably own the puzzles they create and they get paid for doing that.
I've also spoken many times about how bots need to be mitigated when dealing with blockchain gaming. Digital resources become worthless if an army of bots can farm them. Puzzles/mini-games can help play a part in mitigating bots from invading the space, sort of like a CAPTCHA system within another game that creates farmed digital assets.