The OEM Huawei has had a patent for a new kind of smartphone display approved by the US Patents and Trademarking Office (USPTO). It describes a device with a screen that goes all the way down to meet the rear panel. Therefore, the 2 "arc-shaped" pieces of panel that effectively form the sides of the phone act as its buttons, and, possibly, other controls depending on context.
https://www.notebookcheck.net/Huawei-patents-what-might-be-the-most-extreme-form-of-the-waterfall-display-yet.556657.0.html
This is what Samsung was doing a few years ago. Remember the Galaxy S7 Edge? The side display areas were active & configurable. Displayed text notifications & messages, along with the light-bar flashing options. It was very useful.
I assume they received complaints about unwanted screen touches but now a lot of that has been resolved.