I think the only excuse for that huge notch has to be they are planning to put Face ID in there at some point in the near future and don't want the design language to change again when that happens. i.e they are pre-reserving that space in the menu bar.
The latest iPads and iPhones have a LIDAR on the back camera. They can be used to scan the environment. And the FaceID setup for the front-facing camera is used to create those animated memojis that match your face.
If you add it to a laptop, it could actually map the background environment and do some really fancy processing for video calls. Or even improve audio based on the room shape it sees.
