Steem-engine from my understanding is a somewhat centralized side-chain, not proper steem token. That creates some possible issues because of certain level of centralization + steem-engine chain does not have proof of brain distribution but instead the token have to be pre-printed and then shared by a bot, as far as I have understood. For steem-engine to get proof of brains protocol at it's fullest would mean to basically copy what steem is now + the upcoming smt's.