It's interesting that it's amateurs doing this. Big corporations certainly have the tech to make such augmentations, and 10 times smaller to boot. Inductive charging is nothing new (even my old toothbrush uses it), and there exist high-cap batteries much slimmer than this one. It'll be really interesting to see how this technology develops. It's currently used pretty much exclusively by medical equipment, but perhaps this heralds the coming of bionics usable for convenience and entertainment. Perhaps this wonderful future that SF authors promised us is coming afterall. Or a cyberpunk dystopia, but given the amateur, pro-privacy approach to this, I'd lean towards the former.