everything can happen if there is a desire, at this time many companies have joined the crypto world, so I think the bank will also issue their own cryptocurrency. Now that technology has developed so fast as crypto currencies, I am very confident that the bank will someday also issue their own cryptocurrency.
At the same time cryptocurrency will be like our current currency. There will be still different economy for different countries. With bitcoin being the top coin and used more often nationwide it strengthens every economy that uses it. And also it helps to establish more solid economy. But there is a possibility that the countries will, because it is all about competition.