I do not think there will be any disadvantage from it all, the bank will only update and evolve according to the changing times, and bitcoin runs as usual, but in my opinion not everyone uses bitcoin for a small transaction, and they use it more as a place to invest or trade, and I think the bank is quickly adjusting itself to modern times by adopting blockchain technology, so as not to lag behind the latest developments and seek some information to make use of it
I think it will bring some new innovation for the banks itself. and who knows, by doing this, the banks can reach more people without having any border between the country. but it is need time for the banks to realize that crypto currency can brought new changes to them and they need to learn more about bitcoin.