tl;dr; I have no clue, below are just assumptions and questions.
I can be wrong, but at least for the PS5 Pro you need to connect to the internet in order to use the disk drive. Someone correct me if this is wrong, as I don't own a PS5. Also does this limitation apply to the base PS5? If so, maybe Sony wants to prevent the use of third party drives by checking it online. Just an assumption by me.