But it doesn't make it easier for humans to choose colors. For a specific list of detent colors, it reduces the amount you have to memorize relative to full RGB. But to actually reason about colors, you want a non-arbitrary scale; HSV (for instance) gives you hue direction and then you can slide saturation and brightness around.
I don’t know, but I use #ABC a lot, it’s much more convenient than #ABCDEF, never mind [0, 256) or [0, 1]. There are of course more intuitive coordinate schemes and color models, but I find RGB easy enough when you’re not actually doing serious graphic design. This is not about having a GUI color picker either, this is about hand-typing colors.
Maybe it’s just because I’m old and wrote CSS way before it got HSL or other fancy color functions, but personally, RGB colors are really deeply entrenched in my brain.