Generic MALE said:Same reason we keep track of how much weight we increase on the bar, or how many more pull ups we can do, or how many seconds it takes to run a 200m, or how many inches our biceps are... because it gives us something to shoot for while we train. In the process we also learn about ourselves - which areas are the most stubborn for fat loss, what sort of diets and exercise plans thin our skins the most (Oh, if I drink 7-up and do 20 minutes of cardio at level 18 I lose sub-Q fat faster than if I skip the cardio and never take carb drinks),........ also not everyone trains simply for how they look.
I already conceeded that it gives people a goal to shoot for. I see nothing wrong with that - goals are individual and I would never judge someone's goals. For the record, I am not saying BF% is stupid. Hell, I place a lot of value in my BF reading....too much. For me, BF% can be DE-motivating as well as motivating. Especially if it does not say what I was expecting. Just trying to look at it objectively - in reality, it is just another number.
The process of dieting and training DO teach us about our bodies - but that has nothing to do with BF%. If I never got my BF tested I would still know (via clothing and mirrors) if my new diet and exercise plan was working or not. The BF% gives me a number to base that off of - but I could make the decision without it. I can make deductions about my training and my diet without knowing ANY numbers....
I am not sure you can compare all numbers/goals to BF%. I understand your point, and do agree that many people don't train simply for looks. But if I am training for a speed event (say 200m race). I know the record, I know what I need to beat to win. I know what to shoot for. The timed event doesn't differ from person to person - the winner has the fastest time. In a BB comp, the winner might not have the lowest BF or even a specific BF%. In most things, it is an exact number that must be achieved to win. BB is not that way. If you are training for a certain look, you cannot say that at X% BF you will be cut and lean - that % can differ from person to person.