El Salvador just made Bitcoin official 'legal tender,' making it the first government in the world to do so. Later, President Nayib Bukele declared that the state would begin operating Bitcoin mining using geothermal energy. The action has been criticised by the IMF, which cites economic and legal dangers as justifications. The International Monetary Fund (IMF) has spent years debating the broader necessity for and rise of cryptocurrencies, focusing instead on the introduction of state-backed digital currencies.