Yeah That is a good point, I actually make with my setup between the 2 Laptops with 4 threads each running at %80 load around $130 though lately per month because of the Monero price increase above 100 usd. I feel like I hit a jackpot pool also, and these are spare rigs..
I would love for some people like you though that actually know alot about crypto (I can tell you know whats up) to revisit Monero CPU mining, its the best right now %100!! I feel like it is a complete hidden gem I have 1gb per core x 4 plus 2 machines so 8 cores with 1gig each mining happy at 140f average and a total of 280w of power. They have been running like this for many months now.