Your insult will then get scored and you'll deal damage to your opponent based upon how good your insult was. (useapotion.com)
It is a fantastic visual cue indicating that you have done a good amount of damage to your opponent and that you might want to continue focusing on that area if at all possible. (totallygn.com)
With that said, advance strikes cause more damage to your opponent but they are also easier to read by your opponents and do use more stamina. (impulsegamer.com)