Large datasets typically for manual transformations before automating it with some python solution. Works exceptionally for massive CSC datasets for instance.
Some financial models, but not often. I am also a massive Excel fan, and do not aim to replace it.
Writing simple documentation and letters with TOC and macros in header footer.
I have been using OpenOffice or LibreOffice for two decades now, on Windows, MacOS, and Linux, and I don't think I've had a single crash or freeze. Ever.