Most coin mining is not practical on home computing devices. Wasting the power generation in this way isn't necessarily the best investment of the surplus power.

Also... realize that this is power to the local utilities is negative cost - not the power to someone's home. They're still paying retail rates. I would be most disappointed to have the power utility turn on something that causes me to consume more power (be it cryptocurrency or all the lights in my house) when I'm still paying retail rates.