I do -- it is my go-to personal document-writing system. Working with others requires either Overleaf or Docs.

Why not plain text? org-mode or similar?

The equation handling is sublime. I am a physicist, so my quick write-ups include plenty of trips into math-mode.

If I am making a to-do list (and not using taskwarrior), vim is it.

My post thesis days have brought me to the corporate world where Word and PowerPoint rule the land.

I work as a quant (developing pricing models for power and gas trading shop) - I use LyX to write documentations for my models. And yes, I did use it to write my PhD thesis and several papers.

Nope, because in the corporate world you need to collaborate or allow others who likely don't know LaTeX to work with the documents you write.

Know a guy who introduced SharedLaTeX at a security consulting firm. Apparently they all liked it.