As a software developer, LaTeX makes writing documents feel elegant in the way good code is elegant. No more manually going back and saying things like "as shown in diagram 4" and updating the number when the number of diagrams changes; LaTeX can do that for you by referencing the object. Citations and bibliography are an absolute breeze to generate. It can generate various kinds of plots and diagrams themselves for you, making it much easier when you then need to make changes to it later.

With the right packages (think: code libraries) you can do all sorts of things. I like the acrodef and ac commands which lets you specify a bunch of acronyms, and then the first time you use them in a document it automatically expands it to the full version, but uses the acronym on all subsequent uses. When writing code snippets, you can have it automatically apply the correct syntax highlighting for the language you specify; though this is admittedly a feature many markdown implementations also have.