Looking at this from a macroeconomics point of view:

Currently, it wouldn't be wise for any bank to create bitcoin debt, i.e. to issue an IOU for bitcoin in return for a promise to return bitcoin (with interest) in the future

This is because the value of BTC is likely to increase a lot in real terms and therefore the bank's liabilities will become unmanageable

So any sane bank would (for now) just sell BTC IOUs in return for real BTC which is immediately collected and custodied by the bank. So the model would be very different from the fiat money supply process, where fiat banks are more about *creating* money than about *moving* money

This could change is a few decades, when the price finally stabilises