Progressive scan is the "p" in 480p.
Using component rather than s-video on a 480i CRT will yield a marginal improvement in pixel clarity, but might not be noticeable. What you're getting is a reduction in color bleeding and video noise. (big difference over composite video)
What 480p really enables is clarity of movement, by sending complete frames to your eyes. This takes away the flicker/blur effect caused by interlacing. The most noticeable difference is in 60fps games like Metroid Prime. In 480i, when you move the camera around the background isn't totally clear when it's moving, its sort of cloudy. In progressive, it's simply CLEAR, creating a better impression for your eyes, closer to the way we perceive real objects that are in front of us.
30fps games do not yield that kind of motion clarity, because TVs (in p.scan) will force the 30fps to fit its 60fps display, by making blended frames in between the real frames. This deficiency is most noticeable in RE4, if you aim upward at trees or columns and you swing the camera left/right, creating a ghosting effect on the tree edges. It's not so noticeable in other games because the gameplay viewpoints aren't stressing these clean left-right object movements.