Spectacles aren't really comparable to Google Glass, they're more like an action camera, such as a GoPro, but dumbed down and really easy to use. What counts as high user engagement for such a product? It's the sort of thing you only take out for events and special outings.
If they are supposed to function as action camera, then they are probably the lousiest ones ever designed/made. While I am sure the weather is always perfect at the Venice beach with enough sunlight. For nearly all other scenarios, where you might want a camera, you might NOT want to wear sunglasses. This is the reason why Google Glass had detachable attachment for sunglasses. The fact that they are tied to sunglasses, makes them useless in most other situations.
How are you going to wear sunglasses (unless of course you are on a beach) to any indoor or late night event/outing without looking like total douchebag??
I'm not sure you understand what action camera's are for, they're not for late night events, that's what the camera on your phone is good for, and you already have one of those. I've taken them Rock climbing, I took them out on a trail ride, I took them to the zoo, Everybody in my town is hockey crazy, I got shots of fans going nuts after a game. I shot a little cooking video, and they were actually coolest for that (or any type of instructional video)- they're simple enough that your grandma could make a cooking video, edit it, and share it.
The downside is you can't really get the video up on youtube or somewhere where it can easily be shared with anyone other than your Snapchat friends. But whatever, there's probably a half dozen Shenzen startups cobbling together open source Spectacles knockoffs as we speak.
Although Soviet filmmakers in the 1920s disagreed about how exactly to view montage, Sergei Eisenstein marked a note of accord in "A Dialectic Approach to Film Form" when he noted that montage is "the nerve of cinema", and that "to determine the nature of montage is to solve the specific problem of cinema". Its influence is far reaching commercially, academically, and politically. Alfred Hitchcock cites editing (and montage indirectly) as the lynchpin of worthwhile filmmaking. In fact, montage is demonstrated in the majority of narrative fiction film available today. Post-Soviet film theories relied extensively on montage’s redirection of film analysis toward language, a literal grammar of film. A semiotic understanding of film, for example, is indebted to and in contrast with Sergei Eisenstein’s wanton transposition of language “in ways that are altogether new.” While several Soviet filmmakers, such as Lev Kuleshov, Dziga Vertov, Esfir Shub and Vsevolod Pudovkin put forth explanations of what constitutes the montage effect, Eisenstein's view that "montage is an idea that arises from the collision of independent shots" wherein "each sequential element is perceived not next to the other, but on top of the other" has become most widely accepted.
