It is a use case.
There are different levels of design craft. The more you, as a designer, train your mind and eyes, the more you see invisible things for regular people.
I can spend days in clearing the white space between glyph/kerning of typography and this notch will distract my eyes constantly. Call it OCD or professional deformation, the notch will drive me crazy.:)
When designing you want every visual distraction to be absent from your screen, for example I use 50% gray for wallpaper to have middle gray reference etc.
You cannot compare iPhone UX with Design process UX. When you use your phone, you have a legitimate reason for compromise. When you use Pro labeled hardware you expect all Pro use cases and Pro UX to be respected.
Don't get me wrong, I like the overall design (even the redesign of the shape of the keys), and there is no doubt that this are top-notch monsters. But for my use-case this is no go.