Human incarnation as a role model
The very purpose of the human incarnation is to preach the humanity. For this purpose, God takes the human form and behaves like a human being. The behavior itself gives the practical direction to humanity. If God appears in energetic form and gives the message, people will not follow it because there is no practical demonstration by a human being. They will think that the message is practically impossible for human beings. Ofcourse, they will hear the message with lot of reverence to the energetic form with extensive excitation. This extensive excitation may also cause disturbance in receiving the message and understanding it. Jesus also performed penance on a hill for forty days.
Both Sai Baba and Jesus preached that a human being should do penance and realize God practically before preaching about God. The penance means the maintenance of faith on God irrespective of severe practical difficulties. Jesus had no food during penance, which was for a short period. Sai Baba took only Margosa leaves for several years during penance. Even Baba did penance in the childhood, which is nothing but the undisturbed faith that He is Sai Baba.
There was lot of torture on Baba to divert Him and Baba never changed. You find Lord Shiva always in the posture of meditation closing His eyes. Lord Shiva is God Himself existing in the energetic human form. In such case, what is the goal of His meditation? He is giving the message to the souls in the energetic bodies to meditate upon God in that way. He Himself is the goal of His meditation.