According to sleep scientist mathew walker, it serves multiple roles, replenishment of resources obviously, but also behavior refinement (whatever you practice

According to sleep scientist mathew walker, it serves multiple roles, replenishment of resources obviously, but also behavior refinement (whatever you practice during the day gets practiced excessively while asleep), and sleep also is a creative and solution search. He mentions that sleep is so crucial that despite how vulnerable it makes organisms to be debilitated 8 or whatever many hours a day, what it provides more than counterbalances that massive evolutionary vulnerability.