Under certain circumstances, this feature can be very useful. The effect can provide users with helpful reminders, or draw the user's attention to something important.
On hover, this button rotates slightly, but not too much as to distract from its purpose. The button rotates just enough to ensure to the user that the div is an interactive, clickable feature.
This animation example also reassures the user. On hover, the tab pops out from the side of the screen, and when the cursor moves off of the tab, it reverts back into the side, letting the user know where that element "resides."