Neocities and such are still non-fediverse platforms, and the users would still have to know how to do html and set up a website.
The idea was that since Mastodon already has the ability to store your micro-blog posts, as well as images and clips (and has a media button to view the posts that contain them), that it would be convenient for users to also be able to store a few articles or documents as well.
I suppose to make it simpler, these other types of files could also just be attachments to posts the way media files are, and there could be a button to view the posts containing them as well. That would be a lot simpler to implement than my idea, but it would be harder for others to find them and for the user to organize and present them.