> Another limitation of Amateur bands is that they can't be used for commercial purposes, so licensed commercial drone operators must be using commercial bands where cryptography is permitted.

I don't think so. I think we can agree that many, many commercial operators use DJI. There are also lots of amateurs using DJI. Both use the same firmware. There is no option for me to encrypt or unencrypt my Phantom which I could easily use commercially if I had my FAA Part 107.