File upload in OJS 3


There are 2 upload windows in OJS 3 : one used during author submission process and many other context (lets call it submission upload window) and another one, used only when reviewer upload their reports (reviewer upload window). See print screens below.
The main difference is that the reviewer upload windows is not requiring Article component or metadata. It is a simplier upload window.
I wonder why it is not used more often, for example in Discussions or when the Editor is sending its decision at the Review stage. Article components selection before uploading seems unecessary to me in those context.
Are there any technical reasons why submission upload window is more used than the reviewer upload window?

Thank you very much.

file_upload_reviewer file_upload_submission