From my understanding, it can help you save enough to pay you back for purchasing it. This, of course, would depend on how you use it ... saving electricity still depends on changing some of your habits.
But, that it has a way to recognize when you're "away" and sets it in away mode while you're gone, will reduce energy usage.
And, you can program it appropriately for your needs so you're not fussing with a thermostat regularly. There are so many great features on it that should help you save money