The Fitbit Charge 3 does that - the display is black unless you tilt or press button - you can display on wrist too - but all the analysis is done ‘cloud side’ and an app shows your progress and viewable as you need it. Bluetooth connection between the two - data is stored up to seven days locally on the Fitbit and transmitted to the cloud either synch or asynch - your choice.
I have one of these wearables 24x7 (as I track my sleep patterns too for health reasons) on my right wrist, and my watch on my left. I have no plans to buy a smart watch.