Alternately, sleep is the optimal ultra-high-efficiency survival state and wakefulness only exists to give creatures enough time to get their affairs in order so that they can safely return to dormancy.

It's easy to think of sleep as a compromise to be defeated because we're culturally preoccupied with the achievements and pleasures of wakefulness, but that's really just us claiming personal preference for one narrow part of a holistic system that's just doing its own survival and propagation thing.

Consider trees, mushrooms, cicadas, snakes, or cats. Chilling out in low power mode as much is possible is maybe not a error to be fixed so much as it is an outcome of efficient design.

I enjoy this flipped perspective.

The default and optimal state of a life form is waiting and efficiently using resources.

Moving around, socializing and reproducing, killing and eating, are all energy expenditures or necessary to be able to prolong the sleep-life. Annoyances, from the POV of the sleep-being.

"Hurry up and idle" for CPU design ended up being great for power efficiency. Nature came to the same conclusion for biological organisms a long time ago.

I think one of our goals is to reduce entropy in the Universe, and being awake lets us do 100x more of that than if we were in low power mode

Consider hibernation. Evolution went to great trouble there to maximize the duration that some animals can sleep for - and it's pretty clearly solely designed to save power.

Which doesn't mean that's the only thing sleep is good for, evolution doesn't believe in separating concerns, but it's definitely a thing it does.