Many people live in houses with poor insulation or other such problems. They may be tenants with landlords who will not fix this, or live in areas where fixing it is regulated in way that increases the cost by 5-10x (think building regulations where new windows must look like old ones).

Come home to a cold house, wake up in a cold house, heating system that overshoots, forgot to turn it off once when going on holiday etc etc. Even if they have a timer system, it probably has an awkward interface or is in located in an awkward place and some of these problems are still relevant.

Not the worst problems in the world but certainly something they wish was solved. And they like sexy little gadgets too, I expect.

I see the market. I have been part of it more than once.