I prefer labelling things with tags rather than assigning a category to each thing.
An entity (like a page on this website) might be categorised in a system like Wordpress. Each page has a category, and that category might itself belong within a heirachy. This tree structure can be beneficial for some kinds of information, but it doesn't feel natural to my mind.
On the other hand, a tag system, where each entity can be assigned many tags, recognises that an entity may belong to multiple groups at once.
For example, if I was to create a page for a vegan recipe, a category system might suggest that it should be in a 'recipes' category, along with all the other recipes. Or maybe it should be in a 'veganism' category so that it is grouped with other notes about veganism.
On this website and in my personal Zettelkasten, I mostly use tags. These 'tag pages' essentially act as tags normally would, but have the added benefit of being able to add new information to the 'tag' itself. I use [[Obsidian]] to work with the notes, and in obsidian, tags are created with #tagname, and pages are created (or existing pages referenced) by typing [[Page Name]], which creates a link to that page if it exists. In Obsidian if the page doesn't exist, it still makes a link, which creates the page once clicked, but on this website I leave the [[]] in place.