When those unfortunate ones need my help. Or when teaching kids in school.
my work offers win or mac only.
I can't speak for OP but there can be many reasons. For example, I'm using a Macbook Air for development purposes, it's essentially dumb compilation/notarization machine. I don't use it for anything else because I find the user interface infuriating and can't get around it (which is weird because I used to be a Mac developer but IMHO the UI has gotten much less practical).
Fanboys, including management, push macs down our throats and there's little you can do when apple fanboys are also decision makers, since they don't listen to reason.