What's more relevant is that Wayland is adamant on ensuring that scanout is an option as often as possible, making it extremely efficient and fast to put stuff

What's more relevant is that Wayland is adamant on ensuring that scanout is an option as often as possible, making it extremely efficient and fast to put stuff on screen. Also, every pixel has a "checkpoint" sampled at the display refresh rate. With tearing, the checkpoint of a pixel differs from its neighbors, with each subsequent pixel (leading to rolling shutter artifacts), whereas without, all pixels show the same sample. At the cost of glitches, tearing and higher render load let's you put slightly newer data in the bottom third or quarter of your screen. Not really something to write home about, especially considering that X11-users commonly run external compositors exactly to get that tear-free behavior.