I think the idea is more like something along the lines of Bitcoin or similar digital currency with well known and defined rules about supply that serves as the

I think the idea is more like something along the lines of Bitcoin or similar digital currency with well known and defined rules about supply that serves as the defacto reserve currency but each country or region still has a local currency. Gives the benefits of a single easy to transact in currency while avoiding the disagreements that arise like in the EU.