Great shooters are able to shoot under pressure, they step up to the big shot in a game and shoot the ball with confidence. That is why it is important to sometimes practice shooting with pressure on the shooter when doing different basketball shooting drills. You can never really fully replicate game pressure, but you can help to simulate it by making the player hit multiple shots in a row, make a set number of shots within a time limit, or something along those lines.
The 3-2-3 shooting drill is going to force the player to make consecutive shots in a row from different spots on the floor, as well as from different ranges. It will help to simulate some of the pressure that a shooter will experience in a game situation.