Very few people carry one on the A.T. I love my BV500, but it's a rare sight on the trail.
I carry mine because I find it incredibly convenient and I've also lost a bit of faith in bear bags as an option for the A.T. specifically, after watching people use absolutely awful bear hangs on this trail year arter year. Sometimes I think people are intentionally trying to get the bears to associate unattended colorful bags with a free meal.