Maybe a country's bank has accepted bitcoin. But the bank of my country has not done this yet. I am not aware of it. But bitcoin price is increasing day by day. The time will come, all banks around the world will accept bitcoin. Bitcoin has many people work with it for a long time. They are waiting for bitcoin to get legal recognition. Bitcoin did not get legal permission in most countries except in a few countries. So if a country's government does not accept bitcoin, then the bank of that country does not have the power to accept bitcoin. Because all banks depend on the government of their country.
i dont think some banks will accept bitcoin because they maybe threatened to bitcoin and they see bitcoin as a rival due to the fact that bitcoin can also become an investment tool but with better privillages than banks or any other investment methods out there .
however there are some banks that sees bitcoin as a good tool in order to help improve their service. bitcoin can be way in order for banks to earn more income because people will always tend to convert their bitcoins via fiats and they can still use banks in order to cash out their money.