Dear Asterias,
There are more enlightend souls here than me but i will try to answer your queries to the best of my ability and knowledge. In my opinion , Baba and Karma are different , The deeds are yours whereas Baba is lord incarnate .How can you compare your deeds with Baba ? so the anology of the apple and the orange stands.
Every person has to suffer their bad karma's , and Baba is all you mention him to be. But God did not create this world and its creatures to be flawless so if you have flaws and you have done bad karma's and you dont even realize them , although Baba knows everything , he is waiting for you to go to him and tell him you have realized your mistakes and you want to open a new chapter in his life. By reducing your sufferings Baba is taking upon those bad karma's of yours upon himself hence he is not gaining anything from it , infact he is suffering . I am yet to meet a businessman who wants to suffer himself and make others prosper.
As to why you need to go to Baba, When you were in your schooling years (maybe u still are , i dont know) did you go to the school , or did the school come to you with the teachers et al and teach you. We went to school because we wanted to learn. similarly we go to Baba to tell him that yes Lord i know i have sinned and i have come to you to get your blessings.and then he analyses how truthful you are , your faith is , your realization of your mistakes are and accordingly points you in the right direction. (as we have exams in school to know , whether we studied or not and if yes how well).
Om Shri Sainathaya Namaha