I think his analogy isn't great. I think what he is trying to say is that gold due to other utilities of the substance has value as a commodity outside of being money. I think.

He does go on to state that the regression theorom doesn't prove that bitcoin can't be a medium exchange and maybe that frame is just flawed.

I think bitcoin is a new thing and class of thing. Digital scarcity is a new concept that wasn't possible before bitcoin.