Modern industrial scale insulated hot water district heating systems can do dozens of kilometers with the water cooling down only by a degree Celsius.

It's always more convenient to ignore externalities. That doesn't mean we should be okay with only bottom-of-the-barrel solutions.

These days it's not rare to have data center heated buildings. I guess crypto bros are just not thinking about this. But technically if could be done there too.

There was a startup in EU which explicitly sold heat from crypto mining to the local energy provider. IIRC it was also here on hacker news some time ago.

Qarnot maybe

I meant this team:

https://terahash.space/en/

oh nice, i didn't know about them