Banks can't ignore cryptos for longer now, they need to adapt, accept major coins or create their own. In both scenarios, they must begin trading in cryptos too. If they choose to launch their own token, they need to give the chance to change existing cryptos into their, at least.
Why bank need to accept crypto? They just need to adapt crypto's technology not crypto itself. Back to bitcoin feature (decentralized) , it'll be disadvantage to bank because they can't control your balance so that's mean income from tax will be decreased.