What is the importance of follow-through when shooting a basketball?

If you still make the shot and see no different then there no need to change it.

When shooting a basketball, follow through is extremely important. It helps muscle memory, so when you shoot from that same spot, your mind has an idea of how hard to shoot the basketball, as well as how high to shoot. Follow through also helps with hand positioning. When following through, you see how you shot the basketball. If the ball goes too far left or too far right, you can reposition your hand next time you shoot the ball. It may not be too much of a visible improvement, but it will definitely help in a game when you shoot and notice that you're making shots more consistently. It isn't something you do consciously, it is something that your mind corrects naturally with better muscle memory and knocking down those same shots on a consistent basis. Hope this helped :)