No, I agree. However, the problem of a single currency for such diverse countries/economies doesn't go away. The big countries like Germany and France are already cheating on the constraints needed.
"The big countries like Germany and France are already cheating on the constraints needed."
It's an interesting system. It is economically rational to cheat within the currency. If one country proportionately has a higher deficit than others the negative effects of the deficit spending are spread among the others. Indeed, at certain calculations one profits from deficit spending in a scenario like this.
The EU has set up a system of monitoring and penalties to avoid this scenario. However, if one can avoid the penalties, or make the penalties to equal less than the benefits, it remains an economically rational standard. I understand the French, and maybe the Germans, have avoided deficit spending penalties by force of their claims how important their large economies are to the Eurozone as a whole.
It's not unlike a mild example of a metropole-colony relationship where the colony subsidizes the colonizer.