Water-king "softener" device

In the new (old) house I've recently moved to there is a Water-King WK gizzmo on the main feed. I've never seen anything convincing about the supposed science of these things so have assumed they are sold by snake oil salesmen, like magnets on fuel and water pipes, and have switched it off and plan to remove it when I tackle the adjacent jammed stop c*ck. Has anyone seen any reputable report that gives any suggestion that they might be beneficial on single flow, rather than recirculating flow, systems?