For me, the reason to own a Mac (besides hardware support and generally liking macOS) is the amount and quality of third-party software. There is a lot of software that I either need or want, and there are no good-enough competitors on Linux, e.g.: Microsoft Office (for work), 1Password, Affinity Designer, Pixelmator, Acorn, LaunchBar, Little Snitch, Tweetbot, Mic Snitch, DeckSet, Paprika (for recipes), Things, PDF Expert, Arq, Dash, Sonos, etc. In addition, a lot of these tools and macOS are very well integrated, e.g. I can directly search Dash or 1Password from Launchbar. I can make a phone call to a person directly from Launchbar, etc.

For some work there are better open source tools, e.g. Emacs as an editor, org-mode for notes/outlining, LaTeX for typesetting, Handbrake for video transcoding. But they all work fine on macOS.