Do you feel fine? You slept enough.
C'mon OP. What's a computer going to tell you that you 3-million year-old endocrine system doesn't already know?
A computer can give me clues as to why I still feel tired after sleeping for 10 hours every night. The right tracker can tell me what my oxygen levels were while sleeping, or how restless I was during the night. It can estimate how much time I spent in each sleep cycle, and identify anomalies in how much REM sleep I seem to be getting, for example.
Many, many people suffer from various sleep abnormalities and insight into their behavior while sleeping can be helpful for helping their conditions, or at least giving them insight into what's going on.
One problem is that I now build tolerance to medication extremely quickly. As in, something will work great for a few nights and 5 days later I'm back to baseline and totally miserable.
Another problem, that my sleep tracker helped identify, is that at least part of my problem is paradoxical insomnia - where you go to sleep and dream about having a restless night not sleeping.
After some initial difficulties getting anyone to take me seriously, I'm now working with a psychiatrist and neurologist who actually understand what happened to me. By using sleep tracker data, we're able to measure actual medication response, which is much more useful for knowing when to make adjustments than perceived response.
It's also useful just knowing when perception differs from reality. I'm so tired all the time anyway that I can't tell a 3 hour night from a 5 hour night.
I wouldn't necessarily recommend the Dreem - it's a bit like a double slit experiment - the discomfort of wearing it is enough that it in itself worsens my sleep. I'd also not necessarily recommend other non-EEG headband trackers - the data is probably a lot less reliable. And the data that the Dreem exports is somewhat limited. I'm actually working on my own tool for working with it that I hope to release at some point.
Philips also has an EEG headband that looks like it might be a bit more comfortable, but it doesn't seem to be available outside the US.
As much as I hate cliches, what gets measured gets managed. And not-quite-accurate data from a wristband might be enough.
Sometimes information can be handy, even if all you're getting is an automated way of collecting information you already had access to.
"Quantified self" style tracking usually isn't going to unlock amazing improvements in perfectly healthy people, where heuristics like 'if you're tired, try sleeping more' work well. But you might be able to squeeze out some benefit- 5% here, 5% there- that you might not have captured without automated assistance.
And if your baseline is way worse than where you could be, then the potential benefits of tool-assisted tracking could be larger, and many 'common sense' strategies just don't help (enough).