Many countries have used the U.S. dollar as currency, and there is not much of a problem - except that they don't have any control of monetary politics of cours

Many countries have used the U.S. dollar as currency, and there is not much of a problem - except that they don't have any control of monetary politics of course. Some also use the euro by agreement (e.g. Andorra and San Marino) and others without an agreement (Kosovo and Montenegro). However, using the renminbi as currency would pose much more problems because it is not freely convertible.