We weigh about 2/3 of our deer I would guess. It's mainly out of curiosity. Our deer aren't big...avg about 80-120lbs (field dressed). Occasionally we get some higher or lower. Some of our check in stations weigh deer, but it's not a law so not very many do anymore.
One thing I have found (at least in our area), the folks that don't weigh their deer always kill really heavy deer.
That $30 scale will humble you real quick.