Thanks. I have one (2 months old) but are yet to trust any values beyond heart rate.
Nelson,
Congratulations on your Apple Watch!
I've been wearing one for the last 8 year, and yes, heart rate is probably the only thing you can trust, but sleep tracking is pretty good, it seems. I also like a number of heart rate derived parameters such as HRV, resting heart rate, cardio recovery, etc. Give you a pretty good idea of how your cardiovascular system is working.
Oxygen sensor is pretty lame though. There are days when according to it, I need supplemental oxygen. I'm not sure about temperature sensor as I don't have one.
I must say that I'm a geek, and I like tracking as many health parameters in apple health as possible, and I have more than 6 or 7 years of blood pressure, temperature, weight, body fat, lean mass, etc in Apple Health. Unfortunately, most doctors don't give a rat ass about it. But I like keeping records.
As an anecdote, I had covid 2 years ago. The day I got tested I felt pretty bad. Looking bad, my lowest HRV was that very same day, so there you have a good indicator that the body is under stress.
Enjoy!