Doesn't that swipe between desktops/workspaces/whatever? On that note, I have no idea how anyone is supposed to discover these gestures. I had the same problem when I had an iPhone for a few months (long story): I became afraid to swipe anything because I never knew what anything would do and the lag on the thing meant that some widget could show up under my finger without knowing (something I really dislike about reflowing and progressively loaded websites too). The floating dot thing was also way more invasive than a button too.

FWIW, I have animation time set to 0 on my Android phone to avoid these kinds of behaviors but given that the primary interaction was through them on Apple, it was unavoidable.