Why is that? Im pretty sure it will look the same as RGB scart, and by that I mean, very good. There should be as much information with an rgb signal and it should be easier to decode, as I would guess most tv's use the rgb colour space.
A vga cable is rgb and it looks very good.. The biggest difference is that rgb scart can't do progressive.
But.. In the end, If your tv supports component, get them. If it supports 480p, even better. It might actually look better than on a HDTV if it is a fixed pixel set with a 480p resolution. Or a if it is a CRT as it doesn't have the same scaling issues as fixed pixel sets.