The presence of bitcoin will make many changes to the transaction system, I think bitcoin does not need to use bank services because if using a bank then there will be many restrictions and rules, let bitcoin users free to use.
But probably some banks need bitcoin

. There is a bank named skandiabanken which announced it plans to offer clients the ability to link bank accounts to cryptocurrency holdings. It seems that bank wants to attracts cryptocurrency users to still use bank services, I think they know that the grow of cryptocurrencies will reduce bank usage by people. It just my oppinion.