Well, maybe need is not the right word. But I run apps that I can’t run on linux (high-end video, photo and music apps) and I absolutely hate Windows. So that leaves little choice but macOS.
Plus I prefer to work on a laptop most of the time (I have an iMac too for desktop use and I’ll probably upgrade that at some point for even more power) but I prefer the flexibility of moving around. My business is in the UK but I live in Spain so I mainly work from home here. I like the flexibility to move around (sitting outside, in an armchair, at my desk, in bed etc).
So put those two facts together and you end up with a fully specced out Macbook Pro.