I don't want your product to spin while I scroll down. I don't want animations or boxes to start appearing or disappearing. I don't want helpful tooltips, popups, or "I hope you enjoyed this" notifications to appear as I scroll.
What I want when I scroll is for the page to move, either up or down, in a completely consistent manner. I want to be able to reasonably predict what I'll see as I go up or down.
Apple loves this shit. Fortunately they aren't AS BAD as they once were, but you'll still encounter it on their product pages.
Fading the entire content very fast, so fast that it's barely perceptible is actually better on the eyes.
Blinking hurts. Fast changing contrast hurts. The fade is a natural effect I use everywhere almost. My eyes never complained, rather are grateful for the small effort it takes to get right
This is done to hide the change, not as a creative effect. The human visual system is very sensitive to fast changes. But below half a second, smooth changes are not too noticeable. With this trick, plus a slight amount of distance haze, you can get away with quite low detail distant models. That's part of how GTA V does those long vistas efficiently.
Here's a long drive around the GTA V world.[1] Watch how background objects change. Many distant background objects start out with very low detail. Watch power line towers, for example, which are very low detail until about 100m range. The cross-fade to a better model takes about a half second. Active players don't notice.