As of now, there are two countries in the world have embraced cryptocurrencies, in particular Bitcoin as a legal tender, El-Salvador and Central African Republic (CAR) and Bitcoin be used to buy good and services in these countries. In El-Savador Bitcoin is utilized for various transactions including remittances of overseas workers to their families in Bitcoin. However, it is worth noting that CAR initially adopted Bitcoin but later reversed its decision due to some external pressure from global Financial Institutions like International Monetary Fund (IMF) discourage adoption of Bitcoin or other crypto currencies. In future adoption of Bitcoin and other currencies will depend on many factors, such as regulatory developments, public acceptance and addressing the issues related to its security concerns.

https://coinmarketcap.com/legal-tender-countries/