Gold and silver have been currency for thousands of years and are medium of exchange even when rations are scarce.

in a nation's decline, often it is the national currency that loses value and is of no liquidated value. Most national regimes end with hyper inflation meaning that your dollar has less buying power from the time you eat breakfast to the time it is lunch.

Even today we see a single silver coin gain $10 cash value sometimes in just one day. That's how fast the USA dollar is dying now. And it only gets exponential from here.

As far as converting gold and silver back to Dollars, it's actually quite easy. THere's reddit groups, facebook market place groups, coin clubs in every town, coin shows every week somewhere in America, coin shops. Also i keep business cards of anyone i deal coins with anywhere in my state. So i have a stack of cards of people i'd call if i wanted to sell off a bunch of coins.