Banks don't make any money off coin roll hunting, but they do pick up the cost of handling, and re-handling those coins. They pay a fee for those boxes, and need to have enough on hand to service commercial customers, which contribute greatly to their profits. There are usually just enough tellers, to keep customers moving, most don't have a whole lot of time to stand in line. One roll hunter, occasionally, isn't a big deal. Several, on a regular basis, would be annoying, and disruptive.
If there was a bakery, which put out free samples, but found that their store was mostly crowded with people snacking on the freebies, to the point where paying customers could hardly make purchases. do you think they would continue putting out the free samples? Some people just take one. Others take a whole plate...
Banks are a business, coin rolls are mostly for commercial customers, who pay fees for many other services. Coin roll hunters take advantage of a courtesy service, which costs the bank money, which they don't recover. A fun hobby for some, which others get to pick up the tab for...