I do a lot of writing in vim these days, in part because my fingers already know how to make words move around on the page. I find it easier to do the work in a place where I can rely on muscle memory for routine changes rather than have to laboriously guide the mouse around to do edits.
Once upon a time there was an outlining tool called MaxThink (it still exists, for Windows only) that applied the same kind of keyboard-heavy work to outline editing. MaxThink is unique as far as I know in that in addition to the typical kind of outline commands it also had powerful operations like "bin sort" that operated on the outline as a whole. If you had learned the system (and it was non-trivial to learn) you could re-sort a collection of headings faster than you could pick up any one of them with a mouse.
If you can get to the point where your fingers know how to get the desired results onto the page, writing and editing can be very quick. I'll admit to only learning a working subset of vim – there are lots of commands that I never use – but the ones that I do have in my brain really don't require thinking to take on.