I'm not sure if I agree. I have optical HRM on a activity tracker and knowing my resting HR is very cool. Its good enough for 23h a day. I do use chest strap HR

I'm not sure if I agree. I have optical HRM on a activity tracker and knowing my resting HR is very cool. Its good enough for 23h a day. I do use chest strap HRM for cycling where my tracker fails to record high intensity properly (like hills).