And they only help you get or stay asleep. The actual quality of your sleep can still be horrible. Like not breathing 40x a night like I just found out I do.
[1] https://www.nhlbi.nih.gov/health/health-topics/topics/sleepa... [2] continuous positive airway pressure
I got suspicious after falling asleep at work a few times, just an unbearable sleepiness, like I had just taken Benadryl and some vodka. Turns out I had sleep apnea to the tune of 61 events/HOUR.