[Anderkent]

>That all takes energy and most of that energy probably comes from coal or some other environmental nightmare resource.

Maybe, but it's easier to replace centralised pollution from something like a coal electricity plant, than decentralised pollution of every appliance generating it's own power.

A battery appliance doesn't care if the electricity that coms to it is from a hydroplant, a nuclear facility, or coal. It's decoupled from the source, and so allows you to improve things iteratively.