I have used it but not often. I can’t remember the specific project. But the use case for me was when having many objects overlayed, probably working on maps mockups. It is handy to show/hide/lock a type of layers (streets, water, points of interest, UI overlays) at once, while being able to select individual (sub)groups within directly.
Is this option useful per group? yes
Does this need to be in the inspector? I don’t think so, I have never switched back and forth between the two states. It could in a menu.