As you can see in the last pic (which I am not going to quote anymore ) it is testing the emmission values of the exhaust gasses. And you don't want equipment that expensive to hang 5 cm above the ground.
Imagine what this system would look like on a 335i, its like BMW meets Peterbilt !

Anyway the new rear lights look very good IMO, specially the shape. I do agree a little more white would not harm, now with the leds they can make the glasses any colour they wan't so who not? (but I am sure it will fit montegoblue very good )