This year Kawhi is shooting 0.576 FG and from the three a mind boggling 0.542 all while averaging 31.6 points per game.
Steph is way behind and is averaging 0.451 FG and 0.422 from the 3. He is averaging 33.8 ppg. So he is only averaging two points more per game. Strictly from a scoring stand point, Kawhi is your better option. His percentages are amazing.
Then you add his defense and he's limiting the amount of scoring on the other end. Kawhi is having an MVP type of season this year.