Such bank will have to compatible with crypto ideals like decentralization and self custody. It should work more like Uniswap (and better) so we don't hand them too much of our money/power/control which can affect a well decentralized network if you don't regulate the bank properly with the decentralized network rules. Besides, you have to make sure that the decentralized bank you put your money in don't use PoS or other Consensus mechanism to make it hard for you to participate in full consensus/governance... by making people with large amount of stake or miners to determine the consensus or future direction of the bank