> If it can't be _your_ currency let it at least be a currency no other nation controls
At that point just hoard resources. Holding a bunch of Bitcoin in a crisis is useless for a country if no other country will buy them off you in exchange for tradeable hard currency.
You are right. My point is that if you have international trade of even mild complexity, having a currency is very convenient so trade will end up being denominated in one. No reason it can't be some crypto that is not backed by any nation.
"just hoard resources" really has nothing to do with a world currency to replace the dollar, which is what we are talking about here. In a crisis you can't eat dollars, gold, oil, or bitcoin, so yeah, you kinda have a point, but an orthogonal one.