It is nice if you live in a small town or the middle of nowhere to have resistive heating. There aren't any gas lines running out there to provide your home with a constant stream of gas, so if you want a gas powered solution, you end up having to have a pig (it's this gas tank thing) outside your home, and you have to pay to have LP trucked out to fill it up many times a winter, and if you forget to check the pig and run out of gas, your family gets cold, and then you have to pay extra to get the truck to come quickly.

Meanwhile resistive heating uses the power lines that are run pretty much everywhere, and you pay monthly with your power bill, instead of incurring a larger charge for a longer period of time all at once.

But also, and I don't know if this is true or not, so don't quote me, heat pumps don't work if it is too cold outside, and a lot of the time when it is winter, it is very cold outside.

Basically, resistive heating has its place. As for running calculations to create heat, I'm not sure if that's effective on its own, I feel like you'd need a space heater or two to kickstart your way to having a warm home if the temperature changes suddenly, but apart from that the idea seems pretty sound.

Very common in my area idk why.

Yep, I even wrote a script to do that. But if your thermostat consistently turns on throughout the day and night, as long as that continues to happen, your computer is not adding more heat than the thermostat would have, the thermostat just has to add 100W less of heat or whatever your computer draws.

Most thermostats just turn on/off, they don't have a concept of "regular" vs "full blast" because furnaces and other heating appliance don't, they're also just on or off. So when heat needs to be added, they turn on, and once there's enough heat, they turn off. If you run your computer for a bit, they'll just wait a few more seconds to minutes before turning on again since there's less of a difference to make up.

1. No. I have a several room apartment split into several "zones" for heating purposes and the heat moves around enough without needing to manually move the air. In deep winter I basically have everything with a plug I can get my hands on plugged into the wall. During more milder parts, I'll turn on/off stuff as I leave rooms and I have all the machines tied to a thermostat script so they never run if the room gets too warm. The house's native heat is just electric baseboard heaters. With the layout of my apartment they are actually kind of a pain as you can't put anything near them for fire hazard reasons, so almost all of them are turned off permanently so I don't have to worry about that.
2. A pretty random mix of desktop PCs w/ GPUs, SBCs, androids, and some laptops. The androids I leave on even in summer, they sip electricity and are crazy efficient in terms of computation per watt. Some motherboards are just running out in the open with no case because why not. Lots is hardware I've picked up for free from people who didn't want it anymore. Some of it has problems or is quite old but works for the purposes of generating heat and doing science. I've played around w some servers but the noise is just not something that can be worked around especially for the 1U ones. I really want to set up a fish tank full of mineral oil one year and dunk a bunch of my equipment into there and experiment with that, I've seen some really interesting stats on efficiency gains doing that.
3. Honestly I have no idea about the insulation grade, seems pretty good compared to previous places I've lived. Fairly moderate climate, but it below freezing here for a good couple months. I turn off my rigs once it warms up though my main computer crunches BOINC year round as it has to be on most of the time anyways.
4. I should probably also add that many of my rigs are underclocked to some degree. Absolutely not a thing you have to do, they are 100% efficient at turning electricity into heat either way, but most CPUs and GPUs actually hit their peak computation-per-watt efficiency somewhere between 60-80% of maximum clock speed. I've never messed around with undervolting but I know some people do.

Yep absolutely. If you consider the cost of electricity a "sunken cost" regardless, you can mine crypto and always turn a profit though your total monthly revenue might be on the order of dollars a month even with heating an entire apartment. Many crypto miners utilize waste heat in some fashion or another. They also tend to flock to places with the cheapest electricity, which tends to be over-provisioned renewables which are needed to balance the totally imbalanced demand curves which every power grid is subject to. If you want to run your grid on 100% renewables, that means that your average production must exceed your peak demand. Which also means during non-peak demand, you now are producing more energy than you need, since supply and demand must be constantly balanced on a minute-by-minute basis to prevent grid failure, this means at times the electric rate may actually go negative as the power companies need somebody to soak up the extra supply since turning on/off production has some costs and delays associated with it. Bitcoin mining takes up around .1% of global energy usage, mostly from renewable sources.

Personally, I'd rather donate my computational power to science. But there are cryptos which will reward you for scientific computation so you can have it both ways. !gridcoin@lemmy.ml rewards BOINC and Folding@home for example, they have been doing that for around ten years. Basically, they asked the question "What if instead of minting coins for people calculating hashes, we did it for people calculating science?". There's no separate proof-of-work element so all the energy still goes to science. I collect GRC rewards because it helps a bit with the electric bill but it's not like it makes me any real money.