Blood pressure changes through the day. A single reading taken after rushing, talking, or drinking coffee can look worse than it is, and a single good reading can falsely reassure.
People respond to a number with emotion first: worry or relief. If the app doesn’t say what the number means and what to do next, they either panic or stop checking.
Doctors make better decisions from a pattern than from one reading taken in a busy clinic. That gives home readings a clear moment of value: the appointment.