Blockchains are intended to operate without the need for trust. This does not hold true for exchanges. We trust them to look after our crypto but they can freeze our crypto at will. This happenened when Steem was powered up to help Justin Sun. Exchanges can change their rules at any time and if we do not comply with these changes we could loss access to our crypto. I think we need a better way forward, which minimizes how exchanges can control our crypto.