Without any doubt this is possible mate. Even there is many country right now in this world now legalized BITCOIN as their payment method. In fact, we called it legal tender world wide. Even Russian government now with the btc adoption and they have accept it. But yah sooner or later , Digital currency will be used over world wide and we may see btc adoption every where soon.
No, bitcoin cannot be similar to the national currencies of states. The national currency can also be in digital form, but there are too many differences between fiat and cryptocurrency for them to ever be similar. Cryptocurrency will always be with fiat and fiat will be dominant, at least as long as the state is the form of social structure.
In Russia, with the adoption of cryptocurrency, things are bad, and in connection with the attack on Ukraine, it will be even worse. In order to make it difficult for capital to flow out of the country due to increasing sanctions, it is likely that they will go for a complete ban on cryptocurrencies. Time will tell. But the fact that cryptocurrency will not be completely allowed there is for sure.