Gold, silver and platinum have never been worth zero. Thing is your paper money, stocks, bonds, etc have no intrinsic value in and of themselves where as precious metals will always have some value. It's all a gamble but your odds are better with precious metals than with paper.
Anyway, my point is that whenever people bring up investing in precious metals in case of TEOTWAWKI or SHTF there's always a chorus of people saying you can't eat gold or during a crisis nobody is going to give you a loaf of bread for your gold/silver and I'm just saying that's not the reason for investing in precious metals.
If you're really worried about everything going to shit, stock pile food, water, ammo and other supplies to survive DURING the crisis ... invest in precious metals to thrive AFTER the crisis.