Why is latex needed? If we use can integrate a good math renderer to docs, why can't people use that instead?
Also, rendering a beautiful word document is quite chalenge.
Rendered latex document looks stunningly clean and professional out of the box.
They also are plain text, which mean they can be diffed, used with git indexed easily, etc. They play well with anything, being text.
You can even read them without having to render them.
And finally, latex check the structure of your doc. If you change it, it will crash, preventing you from commiting dead references.