There are backpacks for skiing that deploy an airbag in the event of an avalanche to "float" the skier to the surface of the snow. As power requirements and circuits shrink, the creative safety options are expanding into other sports.
I think a lot of people commenting above didn't take the time to visit the many videos of crash test that the site of the manufacturer proposes. The thing is incredibly fast and efficient, including on face-first hit. While I agree with some comments (like the long hair effect, the air-cooling on neck, and some others), it seems quite childish to think that the battery will not have been taken care of by the owner just like everyone's mobile phone one. And any hit that would break your neck with the helmet would do without it too.
Pinhead, I agree. My impacts (and probably most) were forehead-against-pavement collisions from going over the handlebars. This helmet looks completely ineffective for that case--it's going to peel back and let your forehead crash.
As a "fashion statement", I would think that a bike helmet would be much less obtrusive than a think neck brace thing. I don't think people generally ride in dresses with a lot of flowing material to hide such as things as this either. Bike gear tends to be lightweight, thin and very flexible. This looks to be pretty much the opposite.
I would be concerned about how this thing transmits forces into the wearer during an accident. I would not only want to check the roll-back in a frontal accident, but also the torque applied to the head and neck when it slides or catches on pavement and obstructions. If it's just a collar as it appears, and grabs the user's head as it also appears, then that could be a big problem. I wonder what kind of CE approval they got exactly?
Maybe the airbag could be integrated with the dress. On the detection of a potential crash event the entire dress inflates, protecting all parts of the rider. Might be good to use in a mosh-pit at a rock concert too...