I bought it because I liked the grouping (& the quad-whore thing like KJam!), even though I have 3 of the shades, a couple of them either separately or in other palettes. When it's not really odd colors that I might use every blue moon or so, but things that are staples, I don't mind. I'd inquired about Kid way back when I'd gotten it in a holiday palette, but it wasn't permanent then so I couldn't get any more of it.
It might be silly, but I have palettes and quads I've put together myself that have groupings of colors that I want to be easy to find, ones that coordinate, and some left separately that are just basic ones I use for whatever purpose. I used to think I had logic behind it all....but now that I'm reading my post, I realize it just might be part of my MAC e/s overkill! *lol*