Do not be surprised by this one country, America is a big and advanced country. Americans do not want to be left out of other countries so America wants to make bitcoin as the national currency.
That is pretty right because Bitcoin is a decentralize crypto and it cannot be claimed by any country. It can rather become an international currency and not a national. Having a status of international currency, it will be accepted by all the countries around the world and might even outshine US dollar. This is a reality that the number of Bitcoin users in America is the most than any other country but this does not mean that Bitcoin will be claimed as an American currency.