Why, no, I'm not a bank specialist, but it seems to me that he will not replace the main currency of the countries, but will be like a cash currency. It is quite difficult to replace all currencies one by one. And it will certainly not be soon, because it is a large-scale work and not everyone is ready for it.
It is foolish to discuss for the hundredth time what can not be in principle. No state will ever replace its national currency with a crypto currency. This would lead very quickly to the collapse of the country's economy. Bitcoin is also far from banking and can not replace banks, like national money. All this is just childish fantasies, which are not based on real economy.