Looking awful has not prevented local dimming from becoming quite common on laptops. Apple has been doing an okay job of it in the MacBook Pro for several years. Lots of Windows laptops have been very hit-or-miss about it, but at least with those you often have an OLED option. I've seen multiple Windows laptops from more than one OEM where opening a terminal window with light text on a dark background means you can easily spot a single line of text getting much dimmer toward the center of the dark window, and lighter near the perimeter where it's close to other light content. And that's for static content; as you mentioned motion can bring more problems as the backlight lags behind the LCD.