Thanks this is a great answer. So are the others, I think I poorly expressed my initial post.
I use Linux on the desktop myself. I can't justify the price, so I don't use Mac. But if my employer gave me a choice in the matter, I'd pick a macOS machine given - why not go for the fancier option? One where the UI, OS and hardware are tightly integrated. I can always download Debian for free any run it on anything. That's what I was wondering and what you've answered.
I use Linux on the desktop myself. I can't justify the price, so I don't use Mac. But if my employer gave me a choice in the matter, I'd pick a macOS machine given - why not go for the fancier option? One where the UI, OS and hardware are tightly integrated. I can always download Debian for free any run it on anything. That's what I was wondering and what you've answered.