In my household it's MS Office. My partner very much enjoys the UX of KDE, but can't switch because she's highly reliant on features in MS Office that I cannot find transliterated well enough to work on Linux. Otherwise, there is no place for Windows in my house.
It doesn't have all the features, but there is a web version of Office now. Might be worth a look?
It isn't sufficient if you're fluent in Excel, which she needs more than any other part of Office.
Aye, feared as much.
back in the day, I had little problem using crossover for office support.
Personally? Inertia. I hate switching tools/systems unless absolutely necessary. If I were a frog you could absolutely boil me.
For me? Gaming and lack of alternatives. I hate MacOS' hostility toward anything not Jobsian, and Linux doesn't have parity with Windows particularly around gaming.
I prefer Linux, but I dual-boot Windows for gaming, since I haven't been able to get my Nvidia card to work at its full capacity on Linux.