The banks depends on the government regulations so once their government said buy Bitcoin, they will follow. But they will not sell gold to buy Bitcoin but they will use another money they have. We don't know for sure if that news is real because no banks will tell if they buy Bitcoin because of their own reason or because of their government. Gold still be a reserve value for the country so they still need gold. But gold also still be used for corruption because who doesn't want to have gold?