What does a 120Hz refresh rate do? It makes scrolling through webpages or Twitter, playing games, and anything that involves fast on-screen movement smoother and less jerky. It’s a genuine benefit and makes extended screen viewing time easier on the eyes, and makes fast-moving mobiles games look sharper and less blurry.

Källa: Apple’s Slick, Smooth iPad Pro Screen Tech May Come to 2020 iPhone | Digital Trends