I had a buddy who had bags of old mercury dimes. His position was that if the SHTF then silver would be the currency of choice, as it was in the old days. Gold is just too valuable to be practical except for very large purchases. I think that's true. So if you are investing in gold for the purpose of having a physical commodity to use if the world ends then go silver instead. But most people aren't thinking of actually using it as currency.
The best money when SHTF(deflation) are Federal Reserve Notes and specie.(coin money)
Those two forms of money, can be spent anytime and anywhere in the United States.
Remember every deflationary crisis in American history has had massive bank failures.
My great grandfather(1882-1966) only got back 8 cents on the dollar, when his bank crashed during the 1929-1933 deflation.
It’s a hedge. I keep some green pieces of paper around, too.