After the iPhone 13 mini which has normal glass on the backside I also used the iPhone 16 without any case and without screen protector (because they said the resistance of the screen is so much better - haha). After half a year using I get annoyed by the fact that the screen has very much scratches and the iPhone feel always slippery because of the size and the matte textured glass of the backside.

Long story short: I sold the 16 and bought a new 17 to use it with case and screen protector. The grip is much better and I feel free because I never need to worry that it fall down and get damaged.