why is there an option to add keyframes after "hit" in a button symble in flash?

I was wondering why is there an option to add more frames after hit? what is the main use for if cus' if I try to play a button that have more then 3 frames I don't see it and if I try to add gotoandplay(9) in a btn it still doesn't work...

thank you for any answer you can give me.