I have never shared any such data with a physician, but I could imagine doing so if I felt I needed to convince the doctor that something isn’t right (e.g. an unusual change in body weight or resting heart rate), or to show that a treatment is working (or not working), using a record of my symptoms and adherence to the treatment plan.
Just today I tried to show the doctor blood pressure readings on my iPhone. He barely glanced (but he normally hides behind his laptop and doesn’t really talk “to” me).