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.
in my opinion, it is a bad and undeveloped reason with that thought, why does the government or banking institution embrace cooperation and develop together for positive results and make all the people who are not disadvantaged for the development of cryptocurrencies and banking institutions prosperous.