Good examples. Even though I can write HEX colors directly, I usually use dev-tools visually to get it right. Gradients is impossible to write by hand.
Timing functions is the most extreme example IMO. Being able to visualize a Bezier curve from cubic-bezier(0.47, -0.02, 0.57, 1.04), and THEN mentally map that to an animation behavior is just not humanly possible :)