Even underdeveloped countries will not like to give up on their currency, your traditional chrtncies remains your power despite how weak it is, as it stands many countries want trading with other country in their currency if possible, some countries has began to think that US dollar is dominating despite not being the most valued currency, that's why when you go to some Arabic or asian countries with the US dollar you must exchange it to their currency for you to purchase or make payments of items and service rendered, so I don't see what you happening soon that's if it will eventually do.