The cardback + figure thing is a display case choice that someone came up with recently because they liked the idea of having both on display. I kinda get it, I mean let's say you have a really nice Ledy Fett and a Ledy card..together they would look really nice in acrylic. They are also only grading the figure I believe so the card has nothing to do with the grading aspect, it's just set up so you have more to look at when you see a loose figure. Overkill? Probably but I don't think it looks terrible.
My biggest concern though: I don't get how any grading company can determine if the card is original to the figure when they are both loose, that worries me slightly.
As for the U grade Emperor, well I don't like U grading so I best not comment!