Segment's access restrictions - accessType=designated vs when.using vs when.recognized

[Azbesciak]

Hi, I wonder what is the purpose of the following fields, and why these cannot be merged.
At least I am under the impression that when.using and when.recognized may be used only when accessType=allowed, but these also mean it is ... designated, because not meeting these conditions you shall not access it, so that way accessType=designated seems to be redundant - and that is the main problem.

Also, looking at the description (Properties defining statuses that match a rule.) and values for recognized, which are
- as_permitted
- as_private
- as_disabled
- as_employee
- as_student

and on using (Properties defining usage purposes that match a rule.)
- as_customer
- at_destination
- to_deliver
- to_farm
- for_forestry

I am having trouble with the clear differentiation; maybe it is no impossible, but also not straightforward.
For instance, as_customer - why is it as using, not as recognized?