"the illuminated surface of the phone no longer forms a rectangle"
It's not just the notch. The corners of the rectangle are rounded (and probably not a very circular rounding for all I know) and presumably Apple will scream to the courts if anyone starts producing another phone the same shape, so the only safe approach for web devs is to work in the central rectangle and just ask for a background colour (or gradient, or clipped image) to fill out the rest of the space.
If *that* isn't done by default, then lots of web-sites are going to look a bit crap and Apple will deserve to get panned. If it is done by default, then I don't see a problem. You shouldn't be depending on a particular part of your background wash being behind a particular part of foreground content.
Biting the hand that feeds IT
