They said it's because a business in the area gets them from them and they have to keep them on hand. Apparently they only get a few from the main bank at a time. I'm suspicioning that the local business is the barbershop I patronize. They get 6 to 10 rolls a week from a bank close to them, and this is the only bank close to them that has halves.
I had a hair cut that day and talked to the barber who picks them up. He said he occasionally finds silver or proof coins in what he gets from them. We had a good time talking about coin collecting in general, without going into the details of coin roll hunting.