For the most part I agree... when people ask "Do I need to lose weight, I weigh X lbs and am X ' tall" I think look in the mirror idiot...
I use the scale for a couple reasons.. First, it's a good indicator for me that I need to be aware of a potential weight gain. Since I usually hang around 204 lbs if I see I'm at 208, I can make some early adjustments to my diet as the gain will likely be body fat for me. It doesnt always show up in the mirror but it always shows up on the scale.
Second, it's a good motivator when I am trying to drop the extra body fat as it is an immediate guage as to how I'm doing, rather than looking for the results in the mirror. If I was 6% body fat and ripped like most getbiggers, I think it would probably make the scale less useful.