Comment: All value is subjective.

The reason gold and silver have utility as currency is they're easily divisible, you can't use 'magic' to create more of them to serve political purposes, and they are reasonably abundant.

Arguably gold and silver have properties aside from the above qualities that make them valuable for usage in electronics and what not, however the above qualities are what make them an effective medium of exchange which is honestly their primary utility to society.

A digital currency designed to inflate, at a predictable rate (due to technological and mathematical constraints) slowly over time has the same features which make gold and silver valuable as currency. At which point its just a matter of perception which do you want to use more.

Arguably a crypto-logically secure currency that you don't have to worry about transporting around is, in my book, better as a pure 'currency' what it lacks is wide 'acceptance' (understandable given that most people who run businesses have money, and it aint in bit-coins) and several thousand years of tradition lending it gravitas.

I mean what makes a euro more valuable than a dollar or a dollar more valuable than a zimbabwe dollar? Perception. The paper and the ink are worth the its what people think they're worth.

PS.
Saying 'If you can't hold it, you don't own it.' is silly. Ownership is defined by society. If the law of the land says you own it: you own it. Unless you wish to contradict the law, in which case the axiom 'if you can't kill everyone trying to take it, you don't own it' is more applicable, in which case ammunition and guns are infinitely more valuable than precious metal.