Blockchains in games sounds like an amazing idea. I kind of love the idea of Cryptokitties, but it does sound like a waste of money. In this video, blockchains are discussed as an actual game mechanic that could be amazing in some type of MMO game. It would obviously take a lot of work for the developer to put out enough content in the game for everyone, but it could work sort of the opposite of the Mordor games. Instead of the enemies growing based on killing you, your individual weapon would grow specific to what you do in the game. Check the youtube video out, it talks about it in more detail :)

(And you can skip ahead about 45 seconds to get to the actual video if you want)