Because this way those of us who still like print can at least have everything in a single file, on our device, viewable whenever we like.
On WordPress we'd have to open or download multiple articles, and even then there's a limited number of ways to save text and pictures in the same file easily. I could do it, but a lot of older readers wouldn't know how, or want to go through the hassle. I don't want to go through the hassle!