The real value of gold/silver goes beyond its immediate utility uses (medical, electronics, weapons components, dentistry, jewelry, etc.). The value is that it best exemplifies the qualities of money. These qualities include: satisfies a valuable use beyond exchange, portable, durable, divisible, fungible (interchangeable), value density such that units are easy to use for transaction, and is a store of value (every use will be possible for eternity since gold does not expire/rot/degrade).
Things like seashells, tobacco, salt that have been used in other economies satisfied these same qualities, but not as well as gold/silver. Seashells are not as divisible, fungible, or value dense; salt is not as durable or value dense; tobacco is not as durable or fungible. Every other type of commodity can be used as money but will lack the performance in one of the necessary categories of money qualities when compared to gold/silver. Even cryptocurrency falls short of the store of value function since they do not have a specific use value beyond simple exchange value (anything can be exchanged, so this facet is not inherent to crypto exclusively).