Let me just say, this vampire power draw thing is absurd. Let's say you leave their example "average battery" charger plugged in for an entire year. Using Apple's charger instead provides a savings of ~2.5kWh.
http://www.wolframalpha.com/input/?i=(315+mW+-+30+mW)+for+1+year+in+kWh
As wolframalpha puts it, this is about the same energy as one fifteenth of a gallon of gasoline. Turn off your AC for an hour a year and you get the same energy savings. I mean, come on.
That said, it's great (for an entirely different but obvious reason) that Apple is promoting rechargeable batteries instead of disposable. The 29$ price point for 6 batteries and a charger shows that instead of making a ridiculous margin (as they do on every single other accessory), Apple cares about making an environmental difference here.