As far as your questions, Krishna is not in need of anything, He is purnam, the Complete Whole. And yet He appreciates our love for Him, just like everyone appreciates if someone exhibits love for them. So He kindly allows us to show that love by considering that if I do not feed Him, Krishna will go hungry, if I do not give Him rest, He will be tired, like that. He reciprocates by pretending to be dependent on me, my slave, just to give us opportunity to find the real object of our loving propensity and to take pleasure by pleasing and serving Him. Everything we do should be for the reason that it gives pleasure to Krishna.
Letter to Patty Dorgan, 17 November, 1971