He's a pick up artist (PUA). So you get to have sex with women. Big deal. Sure, it was lots of fun, but at the end of the day, you've still accomplished nothing.
A Don Juan will train you to better yourself, to gain actual goals that you care about, to become a real man, and to change your life for the best. That is the cake. Women are the icing on that cake. And, best of all, the women will see how bada$$ you are and you'll naturally attract women of all kinds. Then, not only will you be getting the sex, but you'll actually enjoy your life by having real meaning.
tl;dr: PUA's are boy-man pansies who get nasty girls from bars. D.J's are men who focus on bettering themselves and, in turn, can acquire actual women worth having. Always remember: anything worth having never comes easy.