YUV is a color space used for digital video processing, especially in YCbP 4:2:2 format. It's all about luminance, Cb and Cr, but not color. Like video is not about color.
Imagine a world where colors don't exist, only shades of gray. That's basically video.
Learn about YCbP 4:2:2 See how YUV is used in games Discover YUV compression methods