No, I really do not agree with you. No one is going to question a one oz or half oz silver coin or silver round or silver bar. Today, silver is at about $31/troy oz. No one will do an assay. What do you think they did for hundreds of years? If someone offers ten ounces for something, you might balance it on a simple comparison scale. Precious stones, jewelry, coins, etc, will always have value and be useful for trading. Without fossil fuels, mining will be primitive, and precious metals will be even more valuable. You can't use paper currency, not credit cards, not bitcoin, so you will need something. That will be what humans have always used ---- pretty things, rare things, durable things. Silver coins will rule.