Note that in the case, it's a dollarized country that made an announcement.
(And it would indeed be a lot more suprising if that was a country that's more in countrol of its monetary policy that made a similar announcement).
El Salvador has already given up control of its money supply. It uses US dollars as its currency.
El Salvador already gave up that monetary control by using USD, many other countries also have currencies that are worthless and/or rapidly becoming worthless.