A few years back, my dad showed me a .22 short revolver he purchased back when he was a kid. It wont chamber standard ball ammo: instead it shoots 3 types of roll crimped brass shot shells; the payloads were held in place with tiny over shot cards. The three types of shells were: Blanks, 'Tear Gas', and 'Rock Salt'. The 'Tear Gas' rounds projected a puff of noxious gas from the muzzle, and the 'Rock Salt' rounds fired a small piece of rock salt at a couple hundred feel a second.
He bought it with his paper route money, and used it to shoot dogs that chased him on his bike. It came in a little velvet lined hard case, and he still has a few of each type of cartridge.
Exactly the sort of toy kids are no longer allowed to enjoy - an all metal, realistic looking revolver that shoots non-lethal projectiles from real brass rimfire casings, that they can afford themselves with allowance or odd job money... A Kid could probably get shot for riding his bike around with such a toy these days.
Consider the above mentioned dogs. A loud 'pop', and the sting of some rock salt will teach rover a lesson without killing or maiming someone's pet... No need for the owner to decontaminate the animal afterwards either, as with OC products.
There is a market for these sort of devices... It is small and very much a niche, but there are some occasional limited uses.
BTW - $5 per ball is on par with current production pepper balls used in riot control, and the prison industry (they run about $2 per for the 'practice ammo' filled with baby powder, and $5 for the OC powder payload). When I was a prison guard, the standard procedure was to fire a couple of 5 shot bursts every time you engaged... So basically $50 every time you engaged a target.
There was a certain farmer on the south-east side of Indy who had salt rounds more than 40 years ago. As I remember his seemed way more irritating than these new ones..... They would wreck a pair of jeans too!