@kaia Fiat indexes are usually backed by reserves of (internationally) valuable resources. Putting aside if gold is a good choice for that. You can also back something by the availability/demand of oil, or the price of potatoes, or the profit of a company. But those are tangible things. Bitcoin is like Art, in that it's demand is only sourced by it's popularity. And Bitcoins availability is directly linked to mining difficulty. Might make a detailed post once I have a higher limit.
@kaia according to Forbes, the dollar in particular is backed by production. So the stuff in the US being on sale for dollars. Didn't know that. So aside from the production being localized (stuff made in the US usually sells for dollars), it's similar. I heard that some nation already uses crypto for local payments, so I guess that would give it backing.