> Imagine your country stamps gold coins. If you can take a coin of unknown origin and weigh it against a known good coin, you can pretty easily detect a forgery by it having lower weight.

That hasn't been required since the middle ages. So if modern society reverts back to using gold for trade (because there isn't a currency left, that's what the dollar collapse means), I'd rather have stocked up bullets and kill those who has the stuff i want, rather than trade for it. After all, there's no guarentee that they won't just shoot me in the back after the trade anyway.

What i'm saying is that anyone in a western country that invests in gold is implicitly investing in a hedge against collapse of the dollar (or currency in general). And in the event of a collapse, the gold is going to be useless, if you don't have the bullets to back it up and defend yourself.

Or, speculate on the price - sell when it's high, buy when it's low. But that's literal gambling, not investing.