No country has taken bitcoin as a legal currency for general transactions because of the complications that go along with it. It cannot be adopted yet in that way because it is still too volatile and for now, the transaction fees are too high. Imagine if you were at your local grocery store and upon paying your bill, you would have to pay almost half of your total bill just to process your transaction and on top of that, it takes hours to confirm. Also, since bitcoin is very volatile and its possible that upon paying, the price would change. It would still be a hassle to use.
right there is no country that uses bitcoin for all transactions in their country, but we have to see that bitcoin has been widely used to make payments between countries, only in certain segments, and this is global, if bitcoin is used in traditional trade it is not right, because Traditional traders are usually small scale so it is more appropriate to use paper money, in contrast to buying and selling between countries on a large scale, this is more suitable to use digital currency, so all currencies have a portion of each in the world of commerce.