Cryptocurrencies and banks are incompatible things. Absolutely incompatible. You should understand that the philosophy of crypto is completely different from the modern financial system.
They are compatible because they have something in common... Both are a way to handle money, and sometimes we want to hold our cash on cryptos and some times we want it on dlls, if we want the money and not the cryptos banks are the easy way to withdraw.
When most whitepaper says "peer to peer transactions" or like "no third party needed" it doesn't mean we cannot connect banks and crypto, right now, there are regulations established by the government that allows cryptocurrency to be used and regulated. Just like what we have here in the Philippines, our local exchange Coins.ph is could be used to connect your account to your bank accounts. Meaning to say that you can directly buy bitcoin from your fiat funds. Wouldn't it be better if other exchange will have this feature? Instead of us separating crypto, we use both because in the end, it will be us that will benefit from these emerging technologies.