There’s an answer to that question. Design. Apple undoubtfully have among the best design team in any company. The notch was designed to be an icon for the new Iphone range after the similar re-cycled Iphone 6 design. Just like the Unibody with backlight Apple logo in the Macbook series and Samsung’s Edge display. They serves more to the product’s appearance then the purpose itself.
Yes, the primary reason of the notch was there is to accomodate the the arrays of hardware for Face ID technology (plus microphone, speaker, etc.) but instead of opting the straight bezel, they have chosen the notch to diffrentiate their latest smartphone from the existing thousands of Android smartphones. It’s a powerful marketing strategy, and it’s work out in Apple favour.