If a country wanted to move off of the euro, it would be pretty easy to create a sovereign currency pegged to the euro 1:1 by the countries central bank. Then in the future they could simply unpeg (or change the rate) if that became advantageous.
> "The EU law has primacy over national law and all decisions by the European Court of Justice, including orders for interim measures, are binding on member states’ authorities and national courts,” chief spokesperson Eric Mamer said.
https://abcnews.go.com/International/wireStory/eu-court-pola...
Also, a Eurozone country can’t abandon with Euro without leaving the EU.
The context here is comparing the the EU with the British Empire.
Statements like “The EU law has primacy over national law” make it pretty clear what it means to be a member of the EU.
Generally countries enter various nominally binding arrangements all the time, like ratifying UN treaties that are considered by courts to be part of national legislation etc. So "full sovereignty" in this sense is not so common.
(Also, EU law is drafted via a representational democracy system, so this use of power has an important quality of legitimacy that law handed down from the empire would lack)
There are non sovereign territories that have the right to become independent- but which are nonetheless non-sovereign.
How will you protect the peg? If moving off the euro is taken as a sign of your weakness, defending the peg against the market shorting you will bleed your central bank dry.
The Swiss central bank can always sell as many Francs as they want at any price that is below current bids and that’s always the case when defending an upside limit. They’re never going to run out of Francs to sell because they can issue without any technical limit.