Government needs centralization for economic, political and social control. Money is what flows through and nourishes a regime. So currency control is the premise and prerequisite of a country. Bitcoin is a decentralized currency so it does not match the views of the rulers of the countries. So far only El Salvador is using Bitcoin because they don't have their own currency (using the dollar). El Salvador will be a test for countries to consider using Bitcoin.
it will really be a sample for other countries to consider using bitcoin in their country.
when El Salvador manages to manage their finances with bitcoins which they do legalize as a transaction tool, I'm sure the big countries will start paying attention to the use of bitcoins more wisely.