It beats having to buy a running watch AND a scuba diving computer AND an oxygen saturation sensor AND some kind of sleep monitor. And it's nice for surfing and sleeping better and jetlag recovery tips and heat aclimation and checking the pressure sensor to see when airplane cabin pressure starts dropping and tons more. After a while I noticed tons of other random interesting things too: when HRV goes down for a few days, I'll know I'll be sick 1 to 2 weeks later, when resting heart rate is like 55 or higher (high for me) I probably did exercise too close to bed time or am having sleeping probems, etc.
IMO super cool that it does all of those and more very well.