With your attitude, we wouldn't have automotive airbags, ABS or any of the other significant safety developments over the last 20 years.
The neck airbag is similar to the upper airbag system employed in high end motorcycle road racing leather suits; designed to protect and stabilse the neck vertebrae when the head is being impacted from a collision.
If you combined the bicycle neck airbag with a helmet, the reduction in neck injury would be significant. It's a very smart idea, and gets my tick of approval, but then again, i've never been concerned about how my image will be perceived by others when it comes to safety.