“Symptoms monitoring” refers to the conscious state of paying attention to your symptoms, not using devices to monitor your vitals.
There is no “symptom monitoring” device anyway. A “symptom” is something a patient reports, it’s not generally quantifiable using sensors. There’s no sensor that will measure if your chest hurts or if you feel nauseous, you have to tell your doctor that you are experiencing these things.
But having a constant personal feed of vital stats can make you pay a lot more attention to those symptoms if it turns into an exercise in paying excess attention to your body. Basically, too much information encourages hypochondria.