comment: >
  
  The US dollar often performs this role in trade between countries with volatile currencies.
  The sur will basically act like the dollar but will not be controlled by the US.
  This is little more than a trial run for South America to not be dependent on the dollar or the yuan in the way that Europe is not dependent on the dollar or the yuan. A new currency makes sense because there is no fiat currency in South America that is stable enough to perform this role.
  The most cynical take is that leftist leaders are looking to create a sanction-proof economy.
context: This is for regional trade only. I dont know how they didnt specify that in the article >
  
  I studied economics and i've never heard of a currency for regional trade only. Are there other examples of this?