Looking for info about the Pin icon in World Outliner

I’m looking for info about the ‘Pin’ icon column in the World Outliner window in 5.1.

I learned from some posts that clicking it can force load unloaded objects.
I’m curious to know more.
Is loading unloaded objects it’s only intended purpose? How should it be used together with loading/unloading of World Partition cells and Data Layers? etc

I did not find it in the official Epic document .
(btw, I found a typo at bottom of that doc: “…disable thai behavior…” )

Wondering the same thing; can’t find info on it in documentation either.