When done frame perfect, I believe it's fully invincible, so if you can do it that way, it's amazing.
However, even if it isn't frame perfect, it's still very useful. If you mix up between the hax dash, ledge stall fair (to bat away an opponent that tries to punish said hax dash), you can stall while making it risky for the opponent to try a punish. Once you're ready or the opponent is unprepared, you can then use one of waveland towards center stage, waveland right on the very edge, normal getup or fair into center stage to get back on.
As a side note, I would recommend practicing the hax dash until you can reliably perform it fast enough that the invincibility covers the point where your waveland hits the ground. That way even if you get punished and sent back out, you'll still have your second jump and a chance to survive.