I had the chance to see the “privacy screen” that Samsung put on the Galaxy S26 Ultra in person at one of the brand’s stores. It has two levels of dimming, and at either level, the screen loses a lot of brightness for the person using the device (facing it; see this video), and although I wasn’t wearing glasses, I got the impression (and I wasn’t the only one) that the drop in resolution with the privacy screen enabled is noticeable (for some, even with it disabled).
For me, the significant emphasis Samsung places on a tangential feature supports a healthy trend I noticed years ago: phones became utilities, and buying one is now similar to buying a refrigerator.