As an interesting historic note, the dollar became the main currency in America because of the silver and gold coins which gave it legitimacy. It was originally a Spanish coin I believe.
Yep, it's an interesting history and I know just a little bit about it--I definitely know that the USD used to be backed by gold, and that supposedly put a cap on the number of dollars that could be printed, and people wanted some intrinsic value with their money. That was huge back in the day--read about the history of the Trade Dollar that the US government minted in the 1800s. It's fascinating.
But today? We absolutely don't need precious metals involved with our money, and I don't think they're going to make a comeback. Yes, we had a mania in the 2000s when gold was shooting up to $2000/Oz and silver was headed toward $50, but that kick pretty much died in 2011 when metals started their downward spiral. They have yet to recover from that, but there are still people around who bought a bunch of silver coins at $49 and are just waiting for metals to rebound.
All of the articles by those bulls keep repeating the same arguments, that fiat always goes to zero, the Fed is printing unlimited dollars, that metals are the best hedge against inflation...blah blah blah. Meanwhile, silver is stuck at $16 and bitcoin and the stock market have been on fire for years now.
So no, my opinion is that precious metals are definitely NOT going to return as regular currency. No way in hell.