I think that like the color swatch, first you don't imagine that it is used to put objects inside that style, but then you read or somebody tells you that it function is that if you have something selected and you clic on it the selected objects became that style. The same will occur with the Dot next to the eyeball, you easily make the analogy between the color swatch and the dot, better yet it can be a square like the color swatch, the analogy will be easier to recognize.