There are a couple of reasons for this:
* No Established Move: The "Super-Spin" is not a common or well-known move in superhero comics, especially not for Power Girl. While she has many powerful abilities, "Super-Spin" is not one of them.
* Character Focus: Power Girl's powers and fighting style generally revolve around her super strength, flight, invulnerability, and energy blasts. She is known for her powerful punches and aggressive fighting style, not for spinning attacks.
It's important to note that, while "Super-Spin" isn't a known Power Girl move, she *has* used other techniques that involve spinning, such as using her super strength to spin around rapidly for a powerful blow.
However, the term "Super-Spin" is not associated with her in mainstream DC comics.