The thesis of this product seems to be that Google glass failed due to poor design. I think that's an idea worth exploring and the execution here does look promising, but I'll hold off on judgement until other people can review the device. Here are my immediate, unsolicited, uncollected thoughts: There are many issues that I worry about with this kind of device, but battery safety and battery life are most important…
Since the glasses are much lighter than, say, a phone, I suspect that damaging and thus shorting a battery as a result of a fall is less likely.
A bad charger, or a construction defect, may of course destroy the battery and set it to fire. If the phone industry is any indication, this happens pretty rarely, and is more or less a solved problem.