Benefits of Diane pills include: 
More regular and lighter menstruation, reducing the chance of anemia or iron deficiency.
Less pain from menstruation (dysmenorrhea).
Reduced oiliness of skin and hair.
Lower risk of pelvic inflammatory disease, ovarian cysts, ectopic pregnancy, lumpy breasts, and uterine and ovarian cancer.
Treatment for hormonal imbalances such as polycystic ovary syndrome (PCOS) and acne.