It doesn’t really help that the last crisis exposed that Eurozone governance is a headache compared to the relative cohesion of a one-country currency, due to the individual countries butting heads about policy.
To look at the government styles of other major reserve currencies (USD, CNY, JPY), state/provincial/regional governors have little to no impact on monetary or financial policy. Florida doesn't have the ability to veto the FDIC saving a New York bank for political points, the same way Germany was very will-they-won't-they over several major bailouts.
The difference is that even when non-Euro countries have different regional leaders butting heads, you still have both fiscal and monetary policy controlled by those elected/appointed from the same country.
