I love this. I use various text editors mostly used by devs (moving back and forth between emacs and sublime on mac and textastic on ipad) for serious longform writing all the time, usually using markdown + pandoc, and it has a bunch of advantages and disadvantages.

IME the main advantages are (1) not having to fight with useless Microsoft word (and similar) behavior, bloat, bugs, etc. and (2) being able to mix in a spot of code as needed, for example compiling different sections together, doing a bit of text replacement and templating etc.

The main disadvantage is that the tooling isn't really there. I've done a stupid amount of yak shaving trying to get things like footnote folding in emacs, word count, etc., the spell checking is waaay behind, outline formats don't really work right (though they also don't really work right in word etc.)

So three cheers for anyone working on making the tooling problem better!!