I get what you're saying. Energy price is set by the market so it's irrelevant what it gets used for. But the free market will happily destroy the environment. This is what you learn on day 2 of economics, which is after the majority of the population left the class, it seems. We account for externalities using governments which are able to "correct" the free markets using various strategies like taxation and regulation. Energy is not taxed anywhere near as highly as it should be because it's not taxed according to use. If it were taxed naïvely you'd find many people couldn't afford to boil water because others drove up the price with less essential usage, so that's just not possible. Bitcoin is taking advantage of this. If it were possible to tax energy according to use (and therefore taking into account the external costs), then I'd agree completely with your argument.
> I think many heating elements will also be doing some computation. The fact that they are not - that is a waste.
This is very interesting. But something doesn't seem quite right to me if everyone was passively mining Bitcoin by heating their home. This requires more thought.
The trouble with thinking about any of this too much, though, is it's all completely absurd in the end. All of this: money, gold, other elements we dig out of the ground just to store in vaults somewhere. Buying commodities we never intend to own, much less use. It's layers upon layers of absurdity just to make sure our neighbour doesn't get a larger slice of the pie than we do. Adults tell children to stop arguing and share their toys. This is surely the greatest source of hypocrisy there is.
The only way out of madness, I think, is just to accept that for whatever reason our current systems work somehow. We aren't cold or hungry. In fact, we have access to hundreds of times more than we really need. The only thing that really needs fixing is sustainability. That's the only thing! What we currently have isn't fair; some people do get bigger slices of the pie. But we all get enough. So just quit your whining, enjoy your pie, and work on sustainability. If we can make this whole thing sustainable, then you can start trying to hyper-optimise your pie allocation, but before that time you're just decorating a sinking ship.