Coolness
I just watched this video from the other thread:
Personally, I feel a streamlined bike needs a side/rollover protection system. On a bike or a scooter, when you crash, you become removed from the vehicle. When you start enclosing yourself in even the most weak of materials, you're trapped. Whatever it is, it doesn't even have to be detrimental to aero (or weight) -it could be integrated into the support structure and be an easy way to add a head bubble to clean up the regions behind his head