The idea of gold/silver now is to ensure if crypto blows up, but realistically if it does, the world is blowing up, and your gold is useless metal anyways at that point, as is your money in general.
If you want to "diversify" into real life materials, diversify into high-quality rifles, ammunition, etc. If shit hits the fan you'll be lined up and shot for being a useless rich person with tons of gold.
That's the only purpose of investing in gold due to it's slow gain compared to crypto, so there you have it.

And no, the plan wouldn't be to specifically use the guns yourself, however they become in high-demand, they're shelf-stable in general, and they will be more valuable than their weight in gold if you want to fund a militia or whatever it may be.
If you can't own those legally, I'd buy them anyways, or buy a large barrel of something highly explosive, that again will be extremely valuable.

Or you know, just invest in crypto and if shit does hit the fan, great you maybe lost it all, but go join your local militia. Odds are you'll have to anyways.