I'm going to make a contrarian argument, so I should preface it by noting that I write technical documentation in Markdown for a living, write an awful lot of fiction in Markdown as well, and write the rest of my fiction in Scrivener, which only superficially resembles a word processor. Furthermore, I've typeset several books with LaTeX.

Having said that, an awful lot of tech nerds (arguably like myself) seem to seriously underestimate what word processors can do.

Back when I did write fiction in a word processor, and even now when I have to send fiction to editors who expect things in Word format because that is the lingua franca of the non-technical publishing world, I don't have to spend an awful lot of time formatting manuscripts. Word processors have templates, and hierarchical styles. I wouldn't need a macro to auto-fill in the preamble because I'd have a template that included that.

But if I did want a macro, I could have it! A lot of word processors do have macro languages! Many of them also have search-and-replace capability which is basically regular expressions with an easier syntax. For all the crap Word gets, much of it well-deserved, it's actually pretty good at editing prose. It's almost like they've been developing it for over thirty years or something.

If you're in a position -- which I am -- to use a plain text editor for all your prose writing, and you prefer it, that's terrific. And you could totally make the argument that if your final copy is going to be LaTeX, you should start in plain text, whether or not you're using LaTeX markup from the beginning. But the notion that Word is some kind of underpowered little toy no real author should ever possibly use is just, well, wrong.