All it would take is a few violent moves and the bank is totally screwed. There's no way loans and crypto will ever work smoothly together.
What most people will want is a bank that seamlessly interacts with fiat and crypto. Since such a bank would be a little fish in a big pond it would be bullied out of business.
Loans and crypto still work very well all the time, at least in this forum if someone can't pay his loan, then the collateral is taken or negative trust, the same thing will be applied if there is a bitcoin bank, yeah collateral works., finally the debt must be paid.
Since the bank serves for fiat currency and bitcoin in another path, so we just have crypto exchanges offers to buy and sell cryptocurrencies that cooperate with the bank.
don't know if there is someone or a community tried to create one, hmmmm but it will still be linked to the conventional bank for fiat currency, right?