I first heard the term “benny” in the newspaper. If it is a live term, I expect it got its second life from news reports.
That may be true today. I recall a conversation two Christmases ago with relatives still living in the area (Claire, Cory, Ania, and, a friend of Carl and Claire’s) and the conclusion was that benny was chiefly known among the older generation. The kids knew the term, but didn’t use it much. I’ve seen it in recent vintage news articles too. But the term was very much alive and kicking when I worked on the boardwalk in the 1980s. And I also recall it being common growing up.