There was a paper, I think it was also linked on HN via quanta magazine, where some researchers seemed to have pinpointed the reason why sleep is necessary to live, at least for animals and insects.

However, it seemed too good to be true (I can only wait to see if there is a Nobel prize) and it's not clear to me what to make of it.

The gist of it was that the fundamental damage from lack of sleep actually originates in the gut, not the brain, across rather different species, (mice and fruit flies) where "reactive oxygen species" (iirc) cause cumulative damage that is eventually fatal.

The researchers claimed they had confirmed causality by reversing the shortened lifespan in fruit flies deprived of sleep by feeding them antioxidants.

I have never seen a paper that seemed to so thoroughly eliminate the possibility of a misleading correlation, but the sticking point for me is, if it is so simple to avoid the need for sleep, why hasn't it been eliminated by evolution in the first place?

(Sleep Loss Can Cause Death through Accumulation of Reactive Oxygen Species in the Gut Vaccaro, Alexandra et al. Cell, Volume 181, Issue 6, 1307)