"Bad money drives out good."
When the euro first came mainstream, I contacted one its creators, a professor at Columbia, and outlined why I believed the euro would be a tool in economic warfare.
My naive but sound argument was simply that competition for returns would create a bidding war for capital in dollars versus euros and endanger the US by leading to escalating interest rates, as the US is highly dependent on manageable interest rates to finance its budget.
I never foresaw the euro being the currency of choice for local thugs -- only government-sponsored ones.
Yet Airbus still sells its aircraft in dollars.