I've a whole stack of compute power in the house. The thought of putting it to use, and potentially even getting a profit from it, has crossed my mind before. I lumped in with Team Reg on the Folding@Home drive during covid. But the fact of the matter was that, even with actual computers, permanently powered, it was generally more hassle than it was worth. I had to pause the client whenever I needed the machine for actual use, and I gradually just stopped turning it on again. When I replaced that machine, the Folding@Home client was never reinstalled.
So, on a machine that's pretty close to an optimal use case for distributed computing, by a guy who's interested in the concept, the idea still ended up being impractical. Add in the fact that the machine is now embedded in a car, with a questionable data connection, questionable ownership / control of the software and a questionable effect on the battery life of the vehicle, and you may be forgiven for coming to the conclusion that this is an idea not worth pursuing.
Let's not even think about what might happen if the car's computers' response times suddenly take a dive while driving because this "distributed computing" module decides to kick in at an inopportune time. Let's take the time to get the bloody thing working right before we distract ourselves on tangential uses, eh Tesla?