Problem with gold is that it is also inflationary only difference is it is mines that "print" more gold instead of a central bank.

Cryptocurrencies are better since they have geometric decay built into the algorithm to make them deflationary by default.

Precious metals are also risky long-term in that we don't know how "precious" they truly are in a solar system-wide context.

We can make well-informed guesses, but until there are boots on the ground of the Moon, Mars, and the asteroid belt, we can't know for sure.

Then again you can create new cryptocurrencies out of thin air.