The value proposition of Nest is the same as that of a basic programmable thermostat: save money on heating/cooling (enough to pay for itself several times over), make your life more comfortable (wake up in or return to a warm/cool house without wasting money), and save the planet (lower bills equals less carbon).

You say thermostats are simple, yet I know lots of people that can't use them. I regularly find my own utterly basic home thermostat set at some crazy level because someone was too hot or cold at some point earlier.

It was a pretty good market,Nest seemed to have early momentum and now seemed to have squandered it.