Useful skills (in making real things) and knowledge (of how real things works) is safe heaven for money, not precious metals or anything else.

Precious metals is worth something only if there exists a persons who wish to own and stockpile them. Of course, presious metals have their own value too, but it is a very specific thing - either it is a luxury, that will be barely needed in times of crisis, or electronics plating that is too thin to be something noticeable on the gold market.

In case of real crisis, it would be really hard to use your precious metal savings. Just imagine a real situation - you have gold and need potatoes, farmer have potatoes and need spare parts for tractor, mechanic have spare parts for tractor but need replacement carbide cutters inserts for his lathe and so on. And there are no anybody who really need gold. Why do you think that you will get your potatoes in exchange of gold, and if you do, how you will convince farmer to accept your gold?

Gold is weird thing - most people can't use it, and it only needed by elite. If elite is exterminated, then who will need that gold and why do you think it will worth anything?

To be more clear, replace gold with another precious metal, say, osmium. Elites don't collect osmium, so, suddenly, there is no any money properties in osmium. You will never exchange it for something. And it is not different from gold in terms of chemical nobelity. Gold have current value only because there exists those who want to collect and own stockpiles of gold. In situation when nobody will want it, gold value will be as value of low quality soft and weak stainless steel, not higher.