The NY Times asks, "Why do we sleep?". No one knows, but sleep deprivation supposedly causes real damage.
Elsewhere, a writer with questionable internet research skills endorses Uberman's sleep schedule: "The Uberman's sleep schedule revolves around forcing yourself to rely on six twenty to thirty minute naps spread throughout the day for your daily dose of sleep. I stuck to thirty minute naps, currently having them starting roughly at 2 AM, 6 AM, 10 AM, 2 PM, 6 PM, and 10 PM every day."
Strangely, it sounds just like my own sleep schedule, if one switches time spent sleeping and time spent awake.