Because that is what is on the Mercedes blue clay model og the Bionic/Boxfish, with the uber-low drag... and I like the looks of it, now that I've seen that video of the Bionic you posted...
This design is getting pretty close. These are images of the latest version of the CarBŒN EV Concept Mk 3.0. It is now using the Smart ForTwo windshield and shows the hinged front wheel skirts; as well as a heavily revised nose that is more similar to the Mercedes blue clay Bionic/Boxfish model. The stagnant point is lower and the front fenders start to deflect the air around the front wheels. And the sides are "swoopier" and the beltline is lower, too. The roof is more curved/arched, and the side windows just behind the 'A' pillar are more convex than before.
I think it looks better and it should be more aerodynamic, too. I left all the tessellation lines visible, so the shape is easier to see. The front and back license plates are correctly sized (which should help understanding the scale). The overall length is ~13'-6" which is just a little longer than my Scion xA.
Here's the latest drawing (of the previous version) that shows the seating layout, and the battery pack under the floor, the surrounding safety structure, and my proposed rear hatch and doors entry.
A better quality rendering, but the full bore one will have to wait until I can smooth the model. So far, the script I have over does it and warps the trailing edges, etc.
I reworked much of the hood, front fenders and articulated wheel skirts, the sweep on the side and the front part of the roof -- and added back some headlights! It is much smoother, now...