Many of these, like RGB or YUV, are intermediate "simplifications", not what you're necessarily supposed to be working in to generate them. It's like a physics calculation where everyone just decides to randomly stop half way through and use that as a transport medium. RGB exists because that's how the display physically operates, it's how bright those literal subpixels should be. Thus the RGB intermediate transport. YUV (particularly 4:2:2 and 4:2:0) is then essentially a lossy-compression format that's very easy to compress/decompress, and that's why it exists.

If you're doing rendering work, like in a game, those do operate in a more physical domain. That's the so-called "Physically Based Rendering" or PBR that you might see if you hang out in game dev circles.