No, because they have intrinsic value as a commodity. That doesn't make them immune to pump-and-dump schemes, but it means you can still trade them on a basis other than their USD market value. For example, you can buy gold to make jewelry that is sold in stores and worn in public. Precious metals also have a very, very long history of being used for currency and as a store of value.

No blockchain-based technology has been able to demonstrate anything close to this sort of intrinsic value. The claims of being an alternative currency have not been fulfilled and show no sign of improving. What they call a "scaling problem" looks unsolvable to me.

Absolutely! The only way you can sell gold is when some other sucker buys it. So when at some moment the price of gold drops to 1 cent per kilogram, all those fools who own it will lose their savings. If you are a smart person, you will immediately sell everything you own for dollars, put them in a bag, and keep it hidden under your bed. Well, maybe you at least shouldn't sell the bed. Or perhaps you could use some of those dollars to make a bed; I'm not sure about these technical details. All I know is that everything is a Ponzi scheme, and that this comment will soon appear at the front page of Hacker News.