They're there for a reason.
Topic on User talk:Derivative
I've made a lot of edits recently so you'll need to clarify what you exactly meant here.
You have been busy, yes. (Thank you!)
What prompted my comment was you removing "Category:Space Cadet" from "Space Cadet (novel)", "Space Cadet (novel)/YMMV", and "Eager Young Space Cadet". With the common category on the pages, people can click on it and see the other pages, so we don't need to clutter the pages with links back to the disambiguation page. Without the category on the pages, people might not even realize that the pages have a name in common.
Thank you for clarifying, because it made it now clear what you meant.
I was under the impression that I was just removing redundancies, and giving pages their correct categories by cleaning it up. You might see that that's been the general nature of my category-related edits. I don't recall this being mentioned in policy anywhere, and it's probably a wise idea if someone does so they don't repeat the same mistake.
On a side-note, a friend who I work with on other projects has potentially suggested the use of navboxes, what would you think how that would apply in the scope of ATT, because I think it is a rather good idea, and likely more effective than categories, which what we could call normies might not use.
I do like the idea of navboxes. I wish we had time to implement them.