Okay, I think you are right about everything being worth what someone will pay you for it. Even items with an intrinsic value, that value is subject to change based on other people's desire for it.

But precious metals do have an intrinsic value. They have value because of their inherent utility and resistance to decay. Precious metals are valued because of the substance's natural properties. Modern currencies and other forms of paper wealth hold value ONLY because of the external value placed on them by others - not because of any properties within the bills themselves. It is this distinction that I intended to highlight.