Fiat currency is faith based currency on the US Dollar which technically has zero intrinsic worth. But considering America has the US Dollar Hegemony on the planet this means:

As long as America has the world’s most “lethal” military presence, the US Dollar will always be the primary global currency.

Even consider when we are evaluating and judging cryptocurrencies we peg it and judge it in the US Dolllar amount when judging the “price” of Bitcoin (in US Dollars).