I don't see why Latex shouldn't be used for that. Whether you write # (markdown) or \section (Latex) to start a new section doesn't really matter for you as a w

I don't see why Latex shouldn't be used for that. Whether you write # (markdown) or \section (Latex) to start a new section doesn't really matter for you as a writer, but the latter already gives you a correctly formatted basic version "for free" (who would be insane enough to use Word for an entire textbook?). If you get distracted by the formatting and looks during the writing process, then just limit yourself to the basic Latex commands (\section, \emph, etc.).