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you are going to be away on business for a couple of extra days with the house empty you can just let your thermostat know to remain on a low setting for a few more days

Which mine can also do. I can also tell it that I'm going to be at home tomorrow so use the Sunday program. Or I can tell it I'm having friends over so run the Sunday program for the next few hours. The only thing I can't do is remotely control it although apparently there was once a telephone remote control module you could buy for it.

My main issue really is with the heuristic guessing logic and the much vaunted 'just in time heating' which was what I was complaining about here. It's a bit like cooking dinner for your partner. If they say they are going to be an hour late that's fine. But if they say 'I'll be a bit late' it throws everything into question. It'll be a sad day for humanity when your thermostat responds to a command by asking 'Yes, but how late is late exactly?'.