"immoral" to "waste" energy? Pfff...
funny how these people decide for THE REST OF US what's "moral" and what isn't...
I think the value of bitcoin these days tracks the cost of producing more of them. That being said, if it costs less than the value of bitcoin, you make a profit by mining them. Simple economics.
Back in the 80's there was quite a bit going on with respect to "Co-generation", that is, using otherwise wasted heat from generating electricity for things that made sense, like creating hot (and chilled) water from the engine's jacket heat and exhaust heat. it works pretty well, and you get electricity and hot+chilled water for the cost of maintaining the machinery as it tends to pay for itself.
I suppose that peltier devices and other kinds of heat pumps could be used in various ways to do the same thing with the heat dissipated by a bank of CPUs mining out bitcoin. This would make ECONOMIC sense (which is ALL that matters when you are trying to make a profit).
"Morality" with respect to energy usage - that just *SICKENS* me! If I buy something, whether it's a computer, or electricity from the local utility, it's MINE, DAMMIT! Who _CARES_ how it's used? M.Y.O.B.!