It's not backed by mathematics any more than gold is backed by chemistry.

Uh, gold _is_ backed by chemistry. If gold were to change nearly any of its chemical properties, it would instantly lose its value. It is stable, generally non-reactive, non-toxic, lustrous, and of generally low abundance - all properties derived directly from its chemistry.

That is actually one of the strongest arguments, to my mind, for why some variant of a cryptocurrency will survive as a store of value. Gold kind of "organically" found its way into value almost precisely because it is backed by the physical laws of nature. Cryptocurrencies went up a level to be backed by the laws of mathematics.

Gold's value comes from being a Schelling point, not from any particular chemical properties - other than, like, not killing you or exploding.

Bitcoin is also a Schelling point.

Sure and cash is backed by a special linen-cotton blend of paper.

So, quite a lot then?

Making gold has always been the holy grail of chemistry. It's only valuable because chemistry says you can't make it easily.