"Legitimate" uses of a commodity that trades more for its properties as money should be thought more of a really crappy put option, that is it sets a low price floor.
For example, it's been estimated that gold's industrial uses would only allow it to be traded in the low double digits per ounce if people didn't desire it for other reasons.
It's just in the case of something that isn't physical and isn't "backed" by any alternative uses, the floor is 0% of the current price instead of 1%, or similar.