its a fad, they will go away once people realize the limitations of the device. It's definitely not ready to replace a smartphone, this is a gimmick...very similar to the iWatch or w/e smart watch crap they are producing now days.
I honestly remember some of my friends saying precisely this about smart phones a few years back... Now, they use smart phones.
I'm not 100% convinced, but I am thinking it's more likely than not this Glass thing will be big and the start of something *huge*. Tom's caters to an audience that considers big clunky desktop PCs the pinnacle of computing and, while I personally love that model, the reality of this shows that many of you are *far* removed from what people actually want in computing devices.