In my case, I use bigger screen devices with somewhat exotic productivity tools that would not necessarily fit well in the walled garden.

On the other hand, an ultra locked down macbook would sound pretty ideal for day-to-day browsing, handling financial tasks, work communications and so on. Really everything except the software development tasks I work on.

On the other hand, I do almost everything over SSH already. I guess I really could easily live with a completely locked down base MacOS install without any issues. Even Terminal.app isn't too bad anymore.