Because when the SHTF gold, silver, ammo and food will be valuable while fiat money will be good for toilet paper and starting campfires. Humans like rare, shiny objects and gold fits the bill nicely, plus it's easy to identify and is finite, you can't just print it up. I notice gold went up 1.84% today while the Nasdaq and Dow only went up 0.32% and 0.29%. The Market is human nature at work in a pure environment (fear and hope), it never lies.