You are of course right. Anyway, providing power through the USB-Hub eleminates power issues with the bmcc4k.
The shield does not (anymore) provide the data rates neccessary for 4k. I recently tried 4k, 50fps, 5:1 and it stopped recording after an hour. This drive, same cable, is able to record 4k, 60fps, 3:1.
Yes I don't need 40GBit/s for recording, but reading at high data rates when copying to the workstation is nice to have

I wouldn't recommend using that for production but for me it might work fine. I could easily swap the nvme-drive and have lots of storage relativly cheap.