I recently tried out a game backed by a block chain. I had uninstalled it quite quickly because it was taking dozens of seconds to load a level because my previous actions had to be saved to the block chain. Maybe they picked a poor implementation of block chain to go with, but sacrificing performance for any of the benefits of being on a block chain is not a trade off I see worth while in games in general. Players care about loading screens far more than they care about their items being on a block chain rather than a database.