It may be premature to say that it's neat just for the sake of neatness. It may not have a direct UI usage, but we could probably learn something about mouse events and drawing by examining the code, for example. Also, from a UI perspective, you migh be able to make mousing more efficient by dragging UI elements around in a cloud around the mouse. (You could fade them out so that they were just barely visible, for example, until you right-clicked or shift-right-clicked to pin them down and use them.) It looked, at first glance, like the effect was running on a Canvas, so I don't know how easy it would be to do outside of one.

Also, call it mkn's first law: There's always something you're overlooking. (Where 'you' is the hypothetical you, not you in particular.) :o)