Allow you to have Cover Images on Collections

I can't seem to get my custom collections to have the ability to add cover images, it's pretty ridiculous in my opinion. I don't know if I'm just understanding the use of this wrong but the Pages collection just confuses me when it comes to collections. I want to create a collection for one of my Businesses and have things like Articles, Blog Posts, Products, etc. as sub-collections, but on the Articles I'd like it to have Cover Image support, that seems to be missing. Also, when I create a page inline in one of those sub-collections, I expected the page to go under the same collection, but instead it goes to Pages with no way to move it.