I cannot tell you how
unproductive I am in Microsoft Word. I use LaTeX, often in overleaf, often natively in linux, often on MacOS. Naturally, the latter has a Word version available in it and as a scientist at the interface of physics and biology/medicine I (un)fortunately have plenty of experience in both. Some of my colleagues carte-blanch refuse to try TeX (interestingly, I've never had a doctor refuse to write in Overleaf with me -- only biochemists).
Writing a paper in Word is like pulling nasal hair out through the back of my throat.
It's eminently possible to do it. Millions of people around the world do. Yet it is death by a thousand tiny, frustrating cuts. From the fact that the keyboard shortcuts are not those of the rest of the operating system (on MacOS or Linux on the online app -- e.g. ctrl+shift+arrow keys to highlight text works differently in Word to every other OS) to the fact that opening the paper, writing something, closing it, and re-opening it doesn't necessarily get you the same bloody document. I was editing something last night (from a biologist -- who had done MRI on Burmese pythons – alas the reconstruction was done in matlab and not python!) and each time I saved, my "tracked changes" went from displaying my name to "Author". I forget the number of times I've seen "Unknown field code changed" on the right hand side. If you want to work with references from many people, forget about it. LaTeX has literally none of these problems. Sure, it has a lot of other problems, but none of these ones. I just can't stand using Word; it is inconsistent, slow, and incorrectly second-guesses you. I'm not saying that everyone and their grandparents should use LaTeX, but the disparity -- and the comparative rareness of alternatives, outside of inDesign and Quark in the professional publishing scene -- does deeply worry me. Office is one of those areas where the Microsoft strangehold is strongest. And it's objectively a bad experience!
Seeing "Proficient with Microsoft Office" on a CV for me is a bit of a red flag; highlighting another job skill is probably a better use of space, at the very least.