For the 45% of people with hypertension without a BP monitor, they probably aren't going to buy something 5-10x more expensive to do the same thing either.
Not to mention that it doesn't change any of the lifestyle or medical interventions we have to reduce BP.
I've just found the whole biohacking crowd to be generally misinformed and lacking foresight on this stuff. It's very simple - you can measure your BP in the morning as soon as you wake up for one week. If its high, you can get medicines or change lifestyle to reduce it. If you're interested in how BP changes with different activities, you could measure that quite easily too, or just look it up. Physical activity increases BP, weightlifting increases it a lot, and none of these temporary increases mean much for overall health. I don't see how getting some more data or a nice graph in Apple Health is going to change anything.