To be honest, if banks were the custodian of my cryptocurrencies, I wouldn't mind because the chances of my crypto being lost is going to go down drastically and if it was in an unlikely event got lost, the banks will have sort of insurance that will be in place to take care of the losses.
I also hope that crypto can cooperate with or build a dedicated crypto bank. So that we crypto users are more secure and comfortable in investing or in terms of transactions. When there are banks that accommodate crypto I believe crypto will be more advanced than now. Because people will be more confident in investing or using the crypto.