Gold has been money for over 3000 years. After the SHTF you can use your fiat money as tinder to start fires.
I will use my ammunition for trade goods.
Gold may come back as a currency after a time.
But it will take time for people to get used to using it again.
Take an ounce of gold to a gun show, and see if you can trade it for a gun and ammunition.
It was an eye opener for me.