It's not wasted any more than it is wasted when you play a game or watch a youtube video or TV. It's just a use of energy which you are trying to make as somehow bad. It's just a cultural preference.
No, because if someone invents a way to power YouTube free of energy, that would be awesome, and it wouldn't detract in any way from the value of YouTube.
But if someone worked out a way to generate BitCoin for free without any energy input, that would destroy BitCoin, because it depends on proof of work, where work is defined as consuming energy.
It's not wasted any more than it is wasted when you play a game or watch a youtube video or TV. It's just a use of energy which you are trying to make as somehow bad. It's just a cultural preference.