I think it could be very useful for those sites with more than one moderator as they could leave notes (sort of Post It notes) to each other about specific posts and once the post has been revised, they could be deleted. It would allow moderator discussion without having to flag posts which we keep for extreme cases.
At the moment we keep an external document with links to the post to comment on. Sometimes a post needs action, take note of suggestions, get a second opinion from other moderators, highlight praise or complaints to other moderators… Maybe it would only be useful to us! 