I do not believe that exactly bitcoin will become the official currency of any state. Most of the coins found are already owned by whales. For the national economy, a more flexible cryptocurrency is needed.
It has been stated by the financial institutional of the bitcoin still not enough to be the currency due to the scalability of bitcoin itself. It's not enough scalable and you can try to read the latest news about that through some reliable articles outta here. i guess you will get a lot of clue about that.