For instance: There's only a finite amount of gold, and until recently (electronics), it had no real applications aside from looking nice. Yet gold has been mined for millennia, historically with slaves (sadly this is still the case in parts of the world) and now with machines. The economic use stems from this, and as gold has always been sort-after, it's desire (value) probably won't change anytime soon. While you can't wear bitcoin, I don't see it disappearing either.