Agree. How about apple explains their formulas and how dependent they are on the heart rate.
I can't agree with calories too low or too high without knowing if the equipment knows the vitals and stats of the person using it otherwise it is a very wild guess.
It can't. All it can do is take your information for age, weight, height, etc, and calculate against your heart rate. Throw in some arm movement I suppose. However, it IS measuring resistance because the harder the resistance, the higher your heart rate will climb. Not sure what else is better than knowing your vitals and heart rate on a continuous basis to get an accurate calorie burn per workout? Way more accurate than ANY exercise equipment that doesn't know who is using them.
The calorie burn of a fit 150# 18yo could be 2-3 times less than a 40yo old man weighing 300 #'s and both doing the same exercise at the same speed.