One point of comparison that's a hell of a point in favor of fiat currencies, is the that because fiat is just based on a really nebulous 'general consensus' rather than any sort of 'hard store of value', the same thing that's a bogeyman (of authorities deciding to cancel out all of your assets by executive decision) can work in reverse.
Most of our forms of fraud protection, like identity theft, bank robbery, etc, basically boil down to the government looking at you and going "boy, that's not fair what happened to you. Even though the closest thing we have to a hard store of value's been taken from you, we're just going to literally rewrite the books and set you back to the state where you had your money." It literally treats storage of money like a database restore.
The beauty of that is they can do that without losing anything (besides slightly inflating the system) - with hard currency (whether gold or BTC), they have to actually deplete their reserve of stored value.
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The most extreme example of this historically, was the national debt crisis britain had during the south sea bubble, where most of the country got wrapped up in a giant stock-buying scheme for a company that ended up having no value. This ponzi-scheme crashed, and it briefly looked like something like half the country was going to go bankrupt.
What was amazing about it was that the government realized they had absolute executive power, and just forcibly reset the economy. They just decreed that all of the debts related to it were cancelled, and dictated that individual assets which had been collateral for the debt (like people's houses) had to be returned to them. Many instances of "stores of currency value" got wiped out, but the important thing the government provided was a floor - you might have all the money you earned on south sea speculation deleted, but they guaranteed the average person didn't end up in poverty.