The biggest problem I find with Performance Points is that I've found it pretty much impossible to improve my skills if I'm going for solely performance points.
Performance Points reward perfection over anything else. Perfection implies little to no margin for error. How do you improve when you only play beatmaps that you can play perfectly?
In short, don't focus on Performance Points. Focus on playing maps that you struggle passing. Don't necessarily just play Scarlet Rose difficulty maps, but focus on maps that are barely outside of your reach. You'll find that the constant mountain-climbing is fun for both casual playing and improving at the game.
Also I personally use no-fail and relax mode sometimes. Just for fun. Just because.