The reason why banks will always be against cryptocurrencies is that, since btc in its nature is a decentralized cryptocurrency and that they will not get anything from it when they allow all people to accept it.
I agree. They see cryptocurrencies as a threat for them. Since cryptocurrencies doesnt really circulate unlike the regular currency, and it is decentralized, theyre afraid that people will not need banks anymore since they can secure their stakes or profit on their own.