This attack is a direct continuation of her standing Hard Punch. She keeps the same pose except she stretches her arm out. It has been removed in Street Fighter V.
This attacks usefulness varies greatly between both games it appears in. In the SF4 series this attack serves as Ibuki's only way to combo into a level 1 red Focus Attack. This is kind of irrelevant since this move can not be comboed into itself. Since Ibuki has a very good knockdown game it is generally more useful to start a link that ends with a sweeping Tsumuji or Neckbreaker.
In SFxT the purpose of this attack is different. Due to the way command normals work in said game this can be timed to catch backdashes and fully punish with a 1 meter tag. It can also be used to break armor on characters like Hugo and Zangief.