The kids rooms are pretty easy. Baby monitors have been a thing for a long time. Making them internet connected just means it's easier for the average person to get it to work on their phone (which may be on a different wifi, in a room just out of wifi range, using an AP with client isolation turned on, ...) which means that much more companies opt to build internet-connected than local-only stuff.

The house? For many, it acts as an alarm system. I also assume that the police will react better to "there's two people robbing my home, I can see them on my camera" than "my alarm app told me a window was broken".