When Per takes into consideration shutting down Kobe in the 2nd half of game 4 in LA in '08 then it will have validity. KG obviously played well in the series but, I'm not sure where the conventional wisdom that he was the MVP came from (although I realize its just for discussion and this is just a blogger).
Paul was in fact the best player in that series.
I don't get into these mundane stats like Usage and Per and +/-. Too many factors play a part in how they are calculated. I'll use my eyes and brain.