I’m sure there are instances where is was extremely successful. However in this example, harden is so concerned about the second part of the two for 1 that he loses his man on the MEM possession and gives up a 3. Yes he hit two 3’s, but he gave up 3 in anticipation of the last possession.
Paul has always done this as far as I can remember through his career. Always been one of the guys to really force that Getting two shots instead of one, even if one shot is a quick shot is going to give you a higher chance of scoring in the long run, that's the strategy. Two chances to shoot versus one is always better. Now, you can run into problems of you are taking two rushed shots instead of at least getting good looks. So you have to manage it well.
More possessions = higher point ceiling. Bad shots can still happen even when running a half court set, turnovers can still happen on half court sets.
It really is just as simple as saying more opportunities to score is better. For example, last night during the game when we were getting stomped in the 3rd quarter I realized we were down almost 9 in FG attempts. No surprise we’re getting beat by ~15 at this point. We were not playing good defense, turning the ball over, and MIA was shooting the ball insanely well. Getting chances to score matters just as much as being able to take advantage of those chances. No attempt = no basket.