Most Ponzis and pyramid schemes are built on something that has a legitimate use. After all, the eponymous scheme by Charles Ponzi was built on legitimate post

Most Ponzis and pyramid schemes are built on something that has a legitimate use. After all, the eponymous scheme by Charles Ponzi was built on legitimate postal reply coupons. So a list of non-monetary uses for gold is not evidence that its monetary uses are not Ponzis. Most financial instruments are at least Ponzi-adjacent in that their value is derived from the expectation that other market participants will pay more for them than you did. Whether it's real estate or equities, precious metals or cryptocurrency, profit requires an infinite cycle of growth that must collapse at some point.