For me it's actually about game development, so I'm running things like Unity and baking light maps and things like that, which I absolutely do on the go in coffee shops or whatnot. The battery life is actually pretty decent. Nowhere close to a macbook but I don't have to be plugged in all the time either.

I'm not sure I'd call it niche. No I'm not playing counterstrike in a coffee shop, but it can be fun to bring it over to a friends house. I haven't bought a desktop since 2014, I like having the freedom to work from anywhere and not have to move files between computers all the time. When I have it at home I have it hooked into 3 monitors and a full size keyboard, and it runs pretty quiet, so it's not really any different from having a desktop in that regard.

YMMV though. Most of what I do with a computer even besides games needs a very powerful GPU. If you're working with docker and webdev I'd just get a macbook. My only point is that apple doesn't have a pure monopoly on performance, as impressive as their new silicon is there's some things it's still not so good at.