I don't understand why elevation data is not stored in the sample using a standard length unit. Why is it stored in HKQuantityTypeIdentifier.flightsClimbed (which is 10 feet)? Surely it is not a memory usage issue.
Treadmill GATT provides elevation in meters. Using HKMetadataKeyElevationAscended for the total elevation gain throws away a lot of data.
Why is there no support for weighted vest or backpack? Changing body weight is not the same and provides incorrect energy. Users want to compare workouts with different weights. I don't see any metadata key for carried weight.