I have a blood pressure monitor that also detects pulse.
Can be useful if you have a problem, but you need to keep a record so you spot the difference between "normal" and "not" and can see if there is a trend developing.
Mine loses its memory when the battery goes flat so I have the numbers and their dates on a post-it in the case. I have no need to use it regularly.
I also took it along to the doc when I had a checkup, to see if it displays (about) the same numbers as theirs (it does).
I've had fingertip monitors, particularly at high altitude, I think it was for oxygen content in the blood, so quite different.