> You can make more of these electrical slow waves through an auditory stimulus, if it comes at just the right time.

I wonder: 50ms of pink noise at the right time to make your sleep more restorative. Why or how should such a “backdoor” have evolved? Sleeping by a crackling fire? Pure coincidence, like a bug in the system that never made enough of a difference to come under selection pressure?

Just a bug or unintended consequence of something else?