[totallyabstract]

A French company made a product along these lines already, but I don’t think it’s been updated since 2018: https://blog.qarnot.com/introducing-the-qc-1-crypto-heater/

It’s true this is as good as resistive heating in terms of heating efficiency, but it is still far less efficient than a heat pump. Unless you are in an area with a large excess of renewable energy it probably doesn’t make sense environmentally to use an asic heater.

[nybble41]

One might use a smaller version as a space heater, rather than for primary heating. In that context it isn't really competing with heat pumps; space heaters are usually resistive.

It looks like the same company still makes some products that leverage waste heat from computation (https://qalway.com/fr), just not ones that specifically mention crypto as the source of the computation.