Not to speak about versioning! I can easily git diff my LaTeX plain text files, but doing so with Word files...
The world of pain I go through when I have to collaborate with partners in government or defence, sending back and forth word files from various word versions and tracking comments and changes leaves me losing the will to live.
Oh if we would only have the GitHub GUI for Office files!
Also commenting sucks, in some versions replies add a comment (which renumbers them all..), and in the next version the comment numbers are not displayed. It's a mess really.
Add-ons like iManage are relatively useless if you work with multiple orgs.