> Government backing can provide one source of confidence. But so can strong crypto, and one could argue that these days people have more confidence in crypto than in governments.
Not quite. The confidence in "normal" fiat currency arises not so much from government backing, but from the fact that a well-managed national currency envelopes the GDP of a national economy. Government really needs fiscal discipline to not break the system (the consequences are well known); the trust part comes from the health of national economy and intersection of interests of all involved players.
Consider a major issuer like USA or Eurozone. The strength of their currencies stems from strength of the backing economies. In theory, the government could try fooling the system and run the printing press amok. In practice, such a government would be very short-lived, as it would piss off just about every person with money.
Save for outliers like Zimbabwe, there aren't really many cases of modern governments running themselves in the ground like that. Usually, runaway inflation is a consequence of a catastrophic event in the economy (bubbles, wars, loss of markets and other externalities).
Now, a super-fiat currency like Bitcoin is not backed by anything like that. It is a virtual construct with finite supply, and crypto is just a production vehicle here. It envelopes no economy, so the all trust here comes from compound interest of people who invest into it.