Re-reading allows you to experience your world-building in a dynamic way. Reading static notes is not as conducive to the emotional factor of your world. And my first rule about world-building is the following:
If you cannot use it to entertain through an emotional connection it's mostly useless. And if you don't read the information in the context they are supposed to be, your world-building it's going to an exercise in futility.
And we had a good world-building, a good story, something that we were writing for ourselves. That's the keyword, the secret codeword that may unlock the 'why' outlines don't work well for many writers. For some, they do. And good for them, but I am of the opinion that Re-reading is the best form of world building.