Harden: PER 21.2 TS% 59.3 | 4.8 rb and 5.1 ast per 36
Demar : PER 17.9 TS% 51.7 | 4.4 rb and 3.5 ast per 36
This is about what I'd expect to see. Demar produces at a similar pace but with worse playmaking and far worse efficiency.
Demar helps the team by drawing the opponent's best defender, but he still has to be able to get into the paint. Penetration creates an easier shot, or opens up passing lanes in the defense. Taking a midrange jumper allows the defense to stay within their comfort zone. You don't create switches, you don't create open men.