Let's split this into two problems: 1) Access and control: I'd argue the likelihood here is comparable between IoT cameras and IoT thermostats. 2) Malicious a

Let's split this into two problems: 1) Access and control: I'd argue the likelihood here is comparable between IoT cameras and IoT thermostats. 2) Malicious application: You're correct that botnets favor no visible change in the host's functionality. However, there are ransomware applications of disrupting a home's physical systems that I submit should be considered before dismissing the idea out of hand. Coupled with problem #1, I think it could be an issue. Five years from now, we'll see where things stand.