False. Gold and silver have intrinsic value beyond their use as currency.
If it wasn't radioactive, poisonous and pyrophoric people would probably all just leap into the Neptunium market.
If it were only worth pennies an ounce, numerous industries wouldn't be paying what they do for it. The fact that many industries value it at several thousand dollars an ounce is self-evident from their continued use of it.
Some bitcoin advocates will talk about how useful it is as a currency, and I wonder how much bitcoin is actually used for purposes other then to hope you can sell it to someone else for more than you paid.
For most people the value is what they can receive for it in trade. Which holds for all money.