As long the crypto community doesn't give the power to someone (it can be a bank or whatever) to have most of the control over Bitcoin and altcoins we are fine. If banks are coming to cryptos it depends how they do it. If it's by offering services or investments or cryptos wallets,... There are many cases banks could be active in.
The reality is banks are already in the cryptos and/or blockchain industry. JPS Morgan, BOA are few of them (JPS Morgan has its own blockchain infrastructure "Aurora"). It doesn't matter so much, banks are in the gold industry as well, so?
It will be difficult to avoid using a bitcoin bank i the future for the majority
of people. Bitcoin usage is moving away from being a currency to being
a sort of investment so i would imagine a lot of 'investors' would have no
problem using banks.
So on my point i see bitcoin banks being part of the bitcoin and crypto
future scene. Its not something i can see myself getting involved in though,
Im happy to control my own bitcoin.