Bitcoin can boost the country's economy or it can break a country's economy, depending on how they manage their investment. If they try trading it or don't take care of it then they could lose a fortune. Alternatively, they could get hacked by different foreign nation and lose their investment money, which could cripple their economy.
I don't think that a country will try do some trading with bitcoin since they are just diversifying their money into different investment. For sure, they will just store their money in bitcoin and keep them at a safe place and the government or a country is not a dumb to get hacked so they will probably store it in a hardware wallet.