Technical document preparation. When you're dealing with stuff like tables, graphs, footnotes, appendices... Word makes it easier. I know there's probably a way to reproduce everything in Google Docs, but it's not as easy/automatic.
Doing references and placing images in Latex, on the other hand, was a breeze once I got a hang of its programmatic behavior.
Maybe it's better in Word now though. As I said, it's been a while since I seriously used it.