It certainly seems to have downsides
One small but signficant - to me - detail is that sometimes I need to be able to adjust the heating in my house even when the internet connection is not working.
In fact, nobody is allowed to have internet connectivity for the first two weeks in a new house ( as far as I can tell ) ( or make that six to nine weeks if you somehow sign up with BT ) so presumably no IoT home furnishings can work in that period either.
It just doesn't seem to add much convenience.