Well, if you watch other NBA games, they all shoot a lot of three's now. That's the current craze at the moment. Logically, it makes sense. If you were to shoot 33% from the three for the entire game, the other team would have to shoot 50% from the two to beat you. Those are good odds for the team shooting the three.
So true and it also helps, that the defender needs to cover the most distance to guard the 3, that the defender isn't allowed to make any kind of contact with the opponent during and after the shooting motion and that the defender isn't allowed to get carried into the space occupied by the shooter in order for the shooter to safely land.
So in the end the best case scenario for the defense is to run the opponent off the line, which most often leads to an open lane to the basket and a 2vs1 situation close to the basket versus the lone rim defender or leads to an easy kick out for 3 as the defense is forced to collapse. Any other scenario is basically leading to just putting a hand up as a defender and hoping for a miss.
So the 3 is the most difficult shot to guard nowadays, it has great efficiency and even if the defense runs a shooter off the line it's a catchup scenario from there on, very similar to a vanilla double team in the post.
After all there aren't many reasons not to shoot as many 3's as possible and therefore there aren't many reasons not to play as many shooters as possible and not to play lineups as quick as possible.