Given the insanity around us, it is possible for EXTREME changes in the economy. IF you want to see examples, look at
The WEimar Republic
Argentina 2000 (there was an excellent essay about the conditions at the time but I can't seem to locate it. A guy described how you survived)
Consider that our US currency is backed by ... uhm, err, uh, hmmmm, ug.. "The full faith and credit of the US" or something like that....
If, GOD forbid, we end up like the scenarios below, paper money becomes worthless overnight. How do you pay the doc for your kid's office visit? How do you buy a cord of wood for your fireplace? Barter will work but the wood guy might not want my circa 1900 scale or matchbox collection
Ergo.. you can have some precious metals, pasta, rice, ammo, etc that would be good for barter.
some random thoughts here
1. one advantage to silver is that you have a lesser 'dollar amount'. ie. an ounce of gold might = $2,000. I don't want to buy a car from my dentist, I want a tooth filled. SO, smaller amounts of silver coin might be useful.
2. The government can suddenly declare all gold and silver contraband.. FDR did just that.
3. You can make yourself a target. In other words, there might be people coming for your gold and silver. You have to be ready to supply them copper and lead in 7.62 or OO containers first.
4. Holding precious metals as paper might be worthless. You need to phyisically hold the assets which can create a serious security issue.
Now, I'm not thinking investment wise in terms of being able to pay my mortgage etc with precious metals. I'm thinking more in terms of the ability to obtain essential services and goods for 3-6 months.