I think I see the point now. Not so much for the sake of having your own blog, which is pretty easy to do with the current long-form kind, but for the sake of having a client that only shows blogs from various users, and doesn't show articles at all.

That would probably require a separate kind, though I would be hard pressed to determine what makes that kind definitionally different than the existing kind, except that people are supposed to put blog content into it rather than articles.

There would still be nothing stopping someone from writing an article using the new kind that is intended for blogs, and then you have articles showing up in your blog client again.