As for my wife, if the kid has dropped 10 lbs and is starving to death (she's only 17 lbs right now), I'm sure that jewlery is gone for a can of formula.
This happened quite frequently in eastern Europe during the Jewish Pogrom of the 1930-40s when the ghetto's were setup under the German Nazi Regime. Those with the most Gold and Silver left to trade for food survived the longest before dying of Starvation. Those with a large amounts of Gold where able to trade their gold even for freedom and passage to other neutral countries such as Sweden and Switzerland.
Gold and Silver ownership has its place in the last ditch effort to survive in absolutely barbaric times.
As mentioned in the third world, the means to survival is definitely food, potable water and shelter. The lack of these resources is due to poverty i.e. the lack of enough wealth to purchase such items. If fiat paper currency becomes worthless through devaluation i.e. hyper inflation then the second line means of trade will become Gold and Silver or other precious metals. This has been historically true.
If a bartering system becomes the predominant system of trade, then you may well find yourself going back in time 2000-2500 years. Primitive times indeed and I would have to say even medieval dark age populations densities also!
That worked because they still have a functioning economy. As was said above, precious metals are a buffer, but anyone that thinks it's the be-all and end-all for economic stability is crazy. IF, however, there is still a functioning economy outside the "zone in question," then it probably does make sense. Ie, Argentina still had a relatively stable economy in the surrounding continent. The Jewish ghettos still had the rest of Europe. Heck, even medieval Europe had medieval Europe.
Anything outside of a pure barter system relies on some sort of item with intrinsic value. Yes, gold and silver are obviously the standard. That's only because society made it the standard. But if the world has some sort of calamitous economic meltdown, who knows. TP and toothpaste might be the new standard.
Is gold/silver a waste of money? No. But I think that, if you're using it in place of dollars (or Euro's, or whatever), then it's kind of silly to think of it's value in dollars. Really, you should be planning "This amount I would give for X item." Get a bunch of junk jewelry from your local pawn shop, not pretty Canada Maples or something (if nothing else, you'd have to start going back to the 2-bits type of system). I bet few people are going to be willing to give up anything for a bunch of 50-'s era nickles.