The advantage of both of these factors combined is that you don't have to think about editing, or the user interface. You don't have to break the flow of thinking about your code. You type code, you edit code, you rearrange code, and you only ever have to think about the code. You don't have to spare brain cycles to think about editing, your fingers just do it.
It's like learning to touch type. There are two fingered typists who can type almost as fast as I can touch type. Or even six-fingered typists who might be able to go a bit faster. But even though they know where the keys are, they still need to keep an eye on the keyboard to type. They still need to think about the keyboard. But once you learn to touch-type, you don't need to think about typing any more. You just... type. Being able to keeping your eyes on the screen all the time just allows you to concentrate on your code, rather on the way you're entering it.
By turning some conscious actions into muscle memory, it leaves your conscious mind able to spend more time on the things you want to think about.
The thing is, I see the value in my guitar playing. But when I code, much of my time is spent thinking about what I'm coding, and much less for the actual typing and editing, so I don't really see the value for vim. That's why I finished the tutorial, but then never used it in actual coding. Purely my own opinion, of course.
Or that a text search is a perfectly reasonable way to move the cursor seven steps right to the next right paren.
> Being able to keeping your eyes on the screen all the time just allows you to concentrate on your code, rather on the way you're entering it.
I don't see anything here that is special or unique to vim or emacs.
Then think in terms of friction - friction that prevents you from doing what you want.
The reason for pursuing this kind of efficiency in an editor is because the task of writing and editing text files is only means to an end as a programmer: your goal is to encode the program you have in your head in a form the computer could run. To persist a castle in the sand you're building. Your editor is usually the limiting factor on how fast can you do that. And this matter because the faster you go, the less friction you feel, the more time you have for the important part - thinking. If you can do this fast enough, cross a certain efficiency threshold, your mind will collapse the task, erase the perception of typing.
Think of what happens when you learn to drive, truly learn. Your car becomes an extension of your thoughts, not something you consciously give inputs to. Now imagine driving by having to type in commands like "accelerate" or "turn left". Now imagine the same, but through submitting paper forms.
More like having you workbench set up just perfectly, less like having irreplaceable tools. But the start up cost is what keeps me out - learning it, trying to integrate it into other tools that I don't fully understand anyway (VSCode in my case), etc etc.