Agreed, Windows Hello is pretty neat. But if laptop makers wanted to shrink bezels even further, a notch is a pretty good bet. While a swiveling camera like the one on old Asus phones makes sense too, it's an extra moving part that will hamper durability.
I'm not saying the notch is the only way to implement Windows Hello or Face ID. And I'm not sure if shrinking bezels is enough of a reason to implement something as divisive as a notch.
Either way, notches aren't that bad. No one complains about them on phones anymore (I personally disliked the iPhone X's notch). But if I had to pick between a notch and advanced facial recognition, I'd be in a tough spot.