It's the best way to know you're covered.
I bought these parts, not fully understanding what would be included. I expected 2 motors, speed controllers, etc. I also got all of the connections that I needed plus 5 servos and a couple of very nice screwdrivers. It's lik having a buddy next you saying, "Here you go! You'all probably need this too!" The parts are of good, solid quality but not super high end. The key word here is: value. It takes the guess work out and replaces it with the good quality parts that you need. In the end, you'll be happy. Isn't that what it's all about?