Bitcoin has substantial advantage over gold for this simple reason - you cannot simply say that you're going to confiscate it as a government because everything is anonymised and such.
I wouldn't put too much faith in bitcoin's anonymity, because if any government decided they wanted to seize their citizens' coins, I'd imagine they'd find a way to trace who owns what (at least for a lot of people, and especially those who use exchanges like Coinbase). Hopefully it'll never come to that, because OP is indeed correct that the gold confiscation that happened shows you how much power the government has. I mean, hey....they make the laws, and it would just take the stroke of a pen to make us all outlaws.
It's a shame that no one seems to care about these things and everyone is putting blind faith into the government, which is rarely rewarded.
You live in France if I'm not mistaken, so I don't know how it is over there with government and people's faith in it, but here in the US I'd say there are tons of people who don't trust our government--and they're right not to. There are so many examples of politicians and other government workers perpetrating all sorts of misdeeds (in addition to all the bullshit policies that have been enacted) that I don't understand how anyone
could trust them.
I don't think I was ever taught about the gold seizure of 1933 when I was a kid in school. Those are the types of things that don't make it into standard textbooks of American history unfortunately. Hell, I'd much prefer that subjects like that weren't even taught in grammar and high schools in the US. What's the point of memorizing all of the US presidents, anyway?