BMI is totally bogus. So are those silly bathroom scales with body fat indicators. The only way to truly measure body fat is get dunked in water (Hydrodensitometry Weighing).
I will try to find the U of C article where they tested the Tanita scale against the dunking method, this is where it was discovered to be quite accurate.
The gripping ones are bogus so far as accuracy but they will give you an indication of going up or down. Key thing to remember with any of the electronic ones is to use them at the same time of day and average out readings over a week.
As for the rest of what you said I totally agree.
BTW, my coloric intake wasn't based on a chart it was based on VO2/Co2 test I took a few years back.