He is not interested in his sleep, he's worried and wants to be about his work. God could have designed a human being that was always fresh and rested and needed no sleep. I'll give you my opinion. He wanted to give a universal reminder to the human race that we are but children and ought to own up to it. We are so frail that we have to become helpless and unconscious and blind and weak every day in order to live at all.
Sleep is a terribly humbling experience.
If God's power is made perfect in our weakness, then surely we may believe this Psalm, that when we hand over our anxieties to God and lay our heads down in peace, God works with all His might through the night on our behalf. The great test of faith is to believe that when we can see only a bleak outcome to some situation and no good coming of it, yet the sovereign God can and will bring out of nowhere, as it were, a turn of events or attitudes that brings great blessing. William Cowper wrote a great hymn that has helped me a lot at this point. He hides a smiling face, His purposes will ripen fast Unfolding every hour. But sweet will be the flower.