Few banks did collect fiat currency in exchange for ‘stable coins’ - for people entering the crypto market.
The rest of the banks do not like the crypto-market but are not in control of it.
However with the introduction of CBDC-s the central bank and maybe the rest of the banks will have control over all of the transactions and take control over the gateways from fiat to crypto and back.
While a person may have a large amount in stable coins on the crypto-market, they may not be able to convert it to actual fiat currency.