On: How to see your iOS8 health data

[minikites]

BMI is only intended to measure health at a population level, it's too crude to have any useful input on personal health.

And height isn't static if you're an adolescent.

[scoot → minikites]

Exactly - and yet BMI is one of the metrics included. Meanwhile a manual input is required, despite having been provided with the relevant data.

[king_jester → scoot]

Perhaps this is a concession so that people who do not want to work with BMI do not have to by default. As minikites says, on a personal health basis BMI isn't very useful so folks may want to skip it altogether.