Obviously, when a disaster occurs, paper money does not become instantaneously worthless in the minds of 99% of people. Even in the immediate aftermath of a national/global catastrophe, there are those who will still believe cash has value, however stupid you think that to be.
Silver and/or gold may or may not be useful, as most folks have NO idea of its value now, let alone after a catastrophe. Again, much depends upon the situation and the people involved. No absolutes here.
I personally think it a mistake to pay for something with ammunition. I, myself, am not going to give anyone the means to shoot me. Period. I also will not accept ammunition as a form of payment. I have PLENTY already. Indeed, if someone offers me ammunition, my first thought is to “remove” them as a threat. I’d rather deal with them now than when they decide to fire it at me.
Cheap water filters, canned/dried food, basic medical/sanitation supplies, tools, liquor, instant coffee, cigarettes, batteries, etc. WILL be accepted in trade . . . . regardless of cash/precious metal situation. I’ve never met a single person who didn’t eat, drink, sleep, freeze, bleed, or experience pain. Most everything else is a matter of opinion, belief and circumstances.
Still, I recommend keeping several thousand dollars in cash spread out in numerous secure locations. Price gouging, weeks of chaos, and bribes could go through cash very quickly. And, that’s not counting prostitutes. (Did I mention storing lube and condoms?)