CO as well.Not only is it a backdoor to your network like @kvr28 said, but it gives other people / entities access to your appliances.
I don't remember if it was this summer or last, but I heard stories coming out of CA that when electricity started getting rationed, rolling blackouts, etc, people with "smart" thermostats would come up to find their A/C jacked up to 78 degrees, turned off, or other shit like that when they didn't do it...the power company was remotely doing it in the name of "energy savings" or whatever other nonsense.
Imagine coming home and wondering why your fridge just doesn't seem to keep things cool like it used to, only to find out the power company was fucking with that while you're at work, too.
Fuck all this "smart" fridge, oven, lights, thermostat, washer/dryer, & all that other nonsense.
I tried warning people on the OG back in 2016 about “smart” devices/appliances. People thought I was full of shit for saying how system operators will be able to remotely control your thermostat, fridge/freezer, washer/drying times, EV car charging. The utility was to have operational control while the government wanted access to the cameras & microphones in those devices.
Utility control was put into place. Never heard more about government access.