Most people know their weight and height already. And again, I agree that there are more accurate measurements, but they are all significantly more complicated

Most people know their weight and height already. And again, I agree that there are more accurate measurements, but they are all significantly more complicated. This time you are suggesting training people to visually estimate body fat percentage. That could work. But it's a heck of a lot more complicated than telling someone to type their height and weight into a website.