Comment by ButlerianJihad

If you purchase a home BP monitor, it will include instructions on how to take readings, like these:

https://www.heart.org/en/health-topics/high-blood-pressure/u...

Then you will notice when your HCP ignores those instructions, like wrapping the cuff around your shirt-sleeve, or prompting you to talk while the measurement is taken, or allowing you sit with your legs crossed.

BP monitors are often poorly calibrated. The instructions for my home monitors suggest bringing the device into the clinic for calibration, and then the clinician says "we don't do that!"

Manual sphygmomanometer readings won't have an automatic digital readout, and require the human HCP to interpret, announce and record the numbers.