I don’t think we’re talking about an above-ground economy here, though. I’m talking about a SHTF situation, where all sorts of barter is going on, and suspect that silver may be ONE of the media of exchange (in addition to toilet paper, other precious metals such as lead, cigarettes, etc.). IF that scenario develops, one would do well to have an easily recognizable piece of “barter” material, and some unknown private mint that Joe Public wasn’t familiar with would never fly. But a Washington quarter without a copper sandwich in it (i.e. pre-1964) is pretty well known at least in the US. Would FedGov like such a deal? Hah!
I do remember back in the early 90s that a local gas station was accepting silver (90%, i.e. pre-1964) dimes for a gallon of gas during one of the gas crises. So it’s already happened, and I can easily envision it happening again.