Writing long documents in Word is painful to the point that people prefer to stick to old tools like FrameMaker.
It's also painful in a different way than LaTeX. While LaTeX is complex but deterministic, Word just eludes your efforts in a way that does not build a coherent mental model but rather a loose set of fuzzy rules learned via frustration.
I deeply believe that this was by design and it is part of Microsoft culture, created to separate programmers from users so that they suffer in their own ways. No wonder Bill Gates became a philanthropist in his later years. He knows better than anyone that future historians will figure out all the evil he expertly inflicted on the world.