When you join JKA, you get access to a lot of the benefits that come with the membership. You also get access to ongoing instruction from instructors who are highly trained and certified, experienced in evaluation for Dan and Kyu rank promotions, you also get the ability to participate in local and international JKA karate tournaments, and a slew of other useful benefits, like being a member of the most qualified Karate organization in the world. However, the best reason to join is to practice karate.