So points in the paint are 2 points. points scored from outside the paint to the 3 point line is 3 points while points behind 3 point line is worth 4 points.
Few reasons this work, it equalizes the height advantage. Tall people do not have advantage scoring in paint. It is a logical scoring system. points in the paint are easiest to score so worth less. Also points in the paint draws the most fouls while points away from basket lesser, so to compensate this points further from basket should be worth more.