So far, the argument being made is this: "It's shiny, and that's why these people would have millions killed. To get more shiny stuff."
Fiat - The term derives from the Latin fiat, meaning "let it be done", as such money is established by government decree.
It's not based in trust. It's based in "use this as the unit of exchange or we'll haul your ass to jail". It's based in power. The world wouldn't collapse without fiat currency. The world used the USD dollar which was backed by gold until 1971, and for pretty much all of history before that. I don't see how there would be a calamity of there was a return to a gold standard.