It is very hard to simulate game shooting pressure when you are just in the gym shooting by yourself or with a teammate, but the 33 basketball shooting drill is a great way to do that. By having to make 3 consecutive shots in a row at each spot, you are training yourself mentally to hit big shots. You become comfortable with having the pressure on yourself to hit an important shot.
Also, with this drill you are able to get a lot of reps at shooting, so you are working on the physical side of shooting the basketball as well. Train yourself as a player to be a clutch shooter with basketball drills like this. Practice putting the pressure on yourself so that when you get in a game, you know that you have already worked on hitting the big shot.