My concern:

-door may not resist a side impact collision as well as a conventional door. In fact it might not resist at all.

-door might not open if the door frame rails are misaligned due to a car accident. In this scenario, even conventional doors might jam shut.

-long term use of this door design is in question because of long term durability questions on its mechanism. To open normally, the window and door must both roll down. If the rails or electric motor itself have problems, (like the window portion does not roll down), you will have problems getting in or out of the car.