Just as I would expect a box of ammo, a bow saw or an oil lantern to work in some but not all trades, I also would expect silver to be accepted in some but not all exchanges.

If a Federal Reserve Note were of dubious value in a transaction, I'd say a bag of junk silver and a reliable scale could be useful. Seems like a good addition to one's preparations for hard economic times. As far as a means for "preserving wealth," I don't know.

The video noted by the OP -- and the fact that this thread topic is increasingly common in the U.S. -- indicate a weakening faith in the U.S. dollar. Some people seem to be starting to pay closer attention and studying to understand how their person lives are practically affected by bankers, politicians and groups beyond their national borders.