If they can enslave 100s or even 1000s of machine mining XMR for them, easy money if you set aside the legality of it.
> RandomX utilizes a virtual machine that executes programs in a special instruction set that consists of integer math, floating point math and branches. > These programs can be translated into the CPU's native machine code on the fly (example: program.asm). > At the end, the outputs of the executed programs are consolidated into a 256-bit result using a cryptographic hashing function (Blake2b).
I doubt that you anyone managed to create an ASIC that does this more efficiently and cost effective than a basic CPU. So, no, probably no one is mining Monero using an ASIC.
Deliberate heat generation.
If it's cold and you're going to be running a heater anyways, then if your heat is resistive, then running a cryptominer is just as efficient and returns a couple dollars back to you. It effectively becomes "free" relative to running the heater.
If you use a heat pump, or you rely on burning something (natural gas, wood, whatever) to generate heat, then the math changes.
I used a rack of GPUs to heat my house for a few years back when gpu mining was decently profitable, and my electricity bill was 3-4x more than with the heat pump - so you have to keep a close eye on the math when you're running at/under profitability.