There are many ways that a golf practice net improves your overall golf game.
Your Head Stays Down- When hitting with a golf practice net you tend to keep your head down more, because you know where the ball is going, into the net. Without a net, the tendency to look up is greater, which overall can lead to incomplete follow through, and/or more slices. So by playing with a net, a person more easily tends to keep their head down, which eliminates those bad aspects, and helps you get into the habit of avoiding them. Looking up to quickly can really screw up your drive.
Pressure Free Golf- When one owns a golf practice net all the pressure is off. First of all your at, or in the comfort of your home. Players tend to play a little tighter, and stressed at ranges. This being because whether you like it or not you are being watched, and some people feel they are being judged. Some people can handle that, and some cannot. Some players are exclusive, and like to go with friends, or even by themselves. Whether your that type of player or not, you still receive the same benefit- less stress/more relaxation/focus entirely on your game.
Trying New Things- With a net you can try so many things, that you would try to avoid on a golf range. Try new shot, new angles, use different clubs, and perfect how high or low you hit your balls. What i like to do is go through each club. I start out with my driver, and i hit until i can hit a target i personally designated on the golf practice net at least 5x. I do this for every club, including woods, and irons. I tend to use a golf chipping net for my irons, and just try to get into the pocket 5x. Overall, when you do this you WILL see your consistency, and shots improve. Your technique, thought process, and confidence in your game will all come so much more easily and natural.