Board Thread:Support Requests - Getting Technical/@comment-2217381-20180617151723/@comment-1117661-20180618131139

Note that the page you linked is about how Semantic MediaWiki extension handles category search queries, not how core MediaWiki displays page lists in categories.

The idea of displaying all pages in category regardless of depth does have its benefits, but it also doesn't work in 100% of cases. That's the issue with it.

Main characters, locations, weapons etc. categories are good examples where a list of all pages of that type is useful. But you can achieve this by simply adding the main category to all articles of that type (note that you can add categories with templates, ex. add "Characters" category with the every use of an infobox for characters).

On the other hand, there are category uses that rely on having that main category as list of "unclassified" pages. Ones that don't fit in any of the subcategories. Various maintenance categories are a good example, like Templates, where it's pointless to list all of them, because they're sorted by type. Listing template documentations in main category would just pointlessly flood it. There are also unique templates that would need a category just for the one.

This also varies for subcategories of "main" categories. Take this for example:
 * Characters
 * Royalty
 * Commoners
 * By house
 * Members of house Stark
 * Members of house Baratheon
 * Members of house Lannister
 * Members of house Mormont
 * Members of house Selmy

List of all characters in "By house" category is pointless, because its sole purpose is to list specific subcategories. On top of that, you could have an article "List of characters by house" that is in "By house" category, where you also show additional info instead of just a list of links. But because it's in a subcategory of "Characters", it'd be listed there too. This is where you start to need a separate subcategory for "All characters".

What this boils down to is that if you want to have a main category with all pages from subcategories, you can do that by adding pages to the main cat as well. But if you had that as a default behavior, you'd need a way to disable that for specific categories where the behavior doesn't work.