I’m not sure what you actually were echoing to get 467, I would expect it to be the category term ID. The function can be configured to return only the term IDs, or entire term objects. If you were to only assign a particular term to a certain group of posts, then yes, that can be used to identify the group. You could conditionally load certain template parts on the single post template when a particular category is assigned, and/or output a particular element class to uniquely style the posts having that term assigned. Since both categories and formats are taxonomies, they can be both used in the same way.
The adding post type support section is significant if you have a custom post type that you want to use post formats with. By default formats only apply to post post_types. To have them work with your CPT, you need to explicitly tell WP to relate the post format taxonomy to your CPT. The same requirement applies to any taxonomy. You can also relate taxonomies to CPTs when the CPT is first registered.
Most of the post format docs page is a general discussion about post formats that apply to any usage of post formats. The page isn’t organized that well, the section on CPTs should be moved further down since it only applies to a less common usage. All common usage verbiage should have occurred first.