[greghausheer]

So many ways it's useful.

Wether you have trouble sleeping or not, it allows you to measure what "good" and "bad" is for you.

If I have alcohol before I sleep and don't use a sleep tracker, I generally assume I have a bad nights sleep. But my interpretation is all anecdotal. A sleep tracker can tell me though that I get up X more times when I have alcohol, I sleep Y less hours in each stage, I have a higher heart rate by Z much, have a lower heart rate variability, etc.

And you may think "so what?" We'll, that's the whole point. Now you know...not just "kind of know" that alcohol is bad for you.

It allows you to confirm what you think may be true, but can't prove.

[Erlich_Bachman]

Do you really need it to prove that drinking alcohol, especially before bed is bad for you? This is a well known medical fact. I don't see the point...