Yes, we do. Everyone uses usb devices, but few are willing to dig through the cable mess on the back every time.
This discussion exist in every case design thread. Just check the others and spare yourself the trouble of this argument.
Why the overly complicated design?
Do something simple and call it a day - no risers, no overheating drives, easier cooling with front mounted huge fan, should be less than 6 liters.
Maybe there's no point to design 95% same case as Dondan's A4.
If indeed you are interested in "as small as possible", you may take a look at:
500W Platinum FSP FlexATX PSU - powerful smaller PSU
R9 Nano - shorter than ITX-length GPU's
Please correct me if I'm wrong, but L3 is same size as L1. With enough space for two-slot card, but only single slot card is supported. And there are smaller vented areas on top and bottom, so previous setup with two/four fans will not be working now. How is that the best from L1 and L2?
There are quite many fanless NUC cases nowadays with all kinds of options: Akasa, Impactics, TranquilPC, etc.
I cannot imagine, why would anyone buy this plastic ripoff.