Ok so the economy collapses. It takes $30,000 to buy a loaf of bread. I have a garden, with real, edible food. You come to me and say "I'll trade you this gold for some food" ... I say "I can't eat that rock, piss off"
Gold isn't worth shit if you're hungry.
Again, someone who didn't read my explanation of what money is.
It is an intermediary good, used to facilitate exchanges where there is not a double coincidence of wants.
Your garden is only good in barter with people who want vegetables. If someone already has vegetables, and meat, your garden won't get you any beef or chicken. You need an intermediary good, that is generally recognized as currency.
Think about a world without paper dollars because that is simpler. You go into the Big Box store, you want a flat screen. You gunna bring in a wheelbarrow of potatoes, carrots and lettuce?
Of course not. Those are perishables. And likewise, you garden will only produce crops that last for so long. Money (gold, paper whatever) allows you to store wealth by exchanging those goods now, and spending the return on them later.
Now if the SHTF, there are other universal barter goods that may be better than gold, and safer to store in a banking collapse.
Cigarettes. Booze. Medical supplies. These are things that would suffer in distribution if there is civil unrest or economic collapse.