I think this only holds if enough other people believe in gold or crypto as a backup system.

If I had some extra zucchini and potatoes, and you were running very low on food, it would take quite a bit to convince me that a piece of shiny metal or numbers in a distributed ledger would be worth the calories I'm surrendering.

Right now, dollars would be worth it, because nearly everyone believes in their utility, despite being a very similar faith-based currency.