One justification for a common currency was put forth in Time or Newsweek in the mid-'90s.I like parts of Europe, but its a large and diverse place. Much like our states, there are good and bad.
Like it or not, in the USA were all connected - same federal laws, same interstate system, same currency. We can disagree on things but once something passes as law, were all in on it, by hook or by crook.
In Europe they tried to do the currency, so all that happened is countries like Greece and Italy can borrow at the same interest rate as Germany. They never got any of the other stuff coordinated. This has propped them up for a number of years - benefitting Germany and bankrupting Italy and Greece. When globalism was expanding and capital was cheap, there system was designed to take advantage of it. So its not too surprising there starting to fall behind, given globalism is now in decline and capital is expensive. Add a war to the mix and here we are.
Our time to suck will come - sooner or later for one reason or the other. Nothing lasts forever.
Their correspondent travelled throughout Europe, starting with a specific amount of hard currency. Can't remember, but let's say it was 100 Deutsche Marks (DM).
He exchanged the DM for the local currency, and that currency for the currency of the next country, and so on, throughout much of Europe - e.g. DM to Austrian Schillings, Austrian Schillings to French Francs, French Francs to Italian Lira, and so on, throughout Spain, Portugal, Greece, Switzerland, and perhaps a few others, and finally back to DM.
At the end of the dozen or so currency exchanges, the original 100 DM were down to around 60 DM, with no value added whatsoever.
The Euro got rid of this problem (and yes, introduced a variety of others).