Category talk:Items

Use
I've been browsing through random articles on items, and the use of this category is rather sporadic: to use Category:Super Paper Mario Special Items as an example, while most of the items there only use that category (and other ones like cat:Cards and cat:Artifacts, though that's not entirely relevant now), there are a couple that have a link to this category, and judging by all the links here, there are many more that use it. What should be the constant: having the category for all items, or having it for none of them? I have read through Categories, and I'm honestly unable to follow it, or at the very least I'm unable to find a section that's relevant to this.