The first is Durant and Curry are easily the best shooters. But more than that they can score in a variety of ways and do it all on offense, on and off ball. Probably the biggest thing is they both know how to move off ball to get themselves in a better position to score when they get the ball. Harden and Westbrook are almost exclusively on ball players so when they lost a step and aren’t able to get by their guys they don’t have anything else to turn to and all they can do is spam the PnR.