Anytime it feels like Smart or Grant or Semi is taking too many threes, I guarantee you it's because the offense is failing to generate the looks the sets are supposed to generate and those guys ending up taking shots as a release valve.
It's either that or isos that slow things way down. I imagine the team has tried to avoid allowing things to devolve into Brown and Tatum isos.
Why can't they run more traditional spread pick and roll? Because the most offensively potent guys aren't quite there yet at handling and passing to do that on a regular basis.