My personal plan not to buy any gold, silver, ammo, tobacco, or anything like that.
I think we underestimate the ease with which ersatz currencies can pop up. Favors, barters, stamps, big round rocks, bitcoin, credit card points, frequent flier miles, swagbucks, and others all function as currencies to some degree. Some foreign countries, especially in the Caribbean, use the US dollar as a currency in addition to their own. Individual US states and even banks had their own currencies before the Federal Reserve.
I think people advocate gold and the other items for reasons other than an actual practical suggestion.