1. It's expensive at £250. I doubt it makes a saving on that scale over 10 years. In fact I suspect it costs more over time (i.e. when it goes wrong and when it gets your routine wrong).
2. Most houses do have thermostats. In fact most of them have remotely programmable ones with week schedules at least and a precise user interface (mine is down to half a degree). Plus every radiator (apart from one) has a thermostat on it.
3. Is this really a problem or a manufactured one? If I'm hot I turn the thermostat down. If I'm cold, I turn it up. If I go out, I get back to a cold house and make some tea until the heating warms up. I'll set a minimum temperature at most.
4. I'm sure this will quite happily piss away your gas if you decide to go on holiday. I bet it didn't see that coming! Perhaps I've got the flu - does it know that?
5. Based on the fact that it connects to the WiFi, I suggest that it quite happily reports your data away somewhere which is surely useful. And I bet it knows who you are. How long before you start getting junk mail from NPower saying "have you tried our new tariff"?
6. There's even more shit to go wrong now which will require a CORGI engineer to come out and fix at great cost.
Sorry but it's an excessive product for a non-existent problem.