Of course, we were answering the original poster's questions.
"Would this improve my chances of getting in? ............ how does it look on an application?"
Obviously having a PPL has it's benefits. Just like some cadets get to test out and skip certain classes because of the classes they took in high school and how they score on the qualification tests. Same with the PPL. There are advantages.
But to specifically answer the original poster.
"It's not going to improve your chances of getting it, and it will look just like any other activities on yours or anyone else's application".
If you want to fly, like to fly, and have the means of getting your PPL because you WANT TO; then you should get it. Shouldn't matter if you are applying to the academy or not. Shouldn't matter if the military is even of interest to you or not.
"Plan your life, activities, curriculum, sports, work, etc. around what you like and want. NOT to try and fill squares and impress others. Do this with your life, and you will be so much happier. Take the classes that interest you. Play the sports you like. Apply to the schools you want to. Don't apply to college or a university if you don't want to. (Not every great job requires a college degree). Major in the field that you are passionate about. DON'T THINK ABOUT MONEY. Apply to jobs that you want."
Do these things, and you will be happy. You will have learned what the vast majority of us have learned by the time we are 50+ and say: "If I knew at 18 what I know now.........". Of course, MOST won't learn that lesson now. At 50+ they will be saying the exact same thing to the next generation. And they won't listen either. But, I've got to try.
Best of luck.