Playing to get more pp will only slow your rate of improvement since you will get in the habit of playing songs that are heavily overrated in terms of pp. As you start to get more pp, there starts to be fewer and fewer of these songs and you'll find people in multiplayer lobbies who can play much better than you at much lower ranks. Even though there a "higher difficulty" songs that you have gotten fc's on, the actual difficulty of those songs is like .5+ stars lower than they actually read. In addition, you spend a lot more time playing a much more restricted map pool this way and so you get good only at playing these maps so even songs with the same actual difficulty will trip you up some. If you want so someday be able to flaunt your skill and not just some number on your profile, play a lot of different songs that you enjoy playing and stop caring about pp. PP will be a byproduct of your improvement.