Banks will provide cryptocurrency and fiat exchange services without any problems. They do not risk anything here and will only take their commissions for these services. For this, banks only need an appropriate regulatory framework. It is already more difficult for banks to perform other operations with cryptocurrency, given the high volatility of prices for decentralized cryptocurrencies.
Of course, banks will not switch to using cryptocurrency instead of regular currency. At the same time, banks use the ripple network to conduct fast transactions. Basically, in this case, they are just applying blockchain technology.
Banks will soon be making widespread use of central bank stablecoins, that is, their digitized currencies.