Why Are Turnaround Needles Good?

[NASA1998]

I don't main Sheik, however I enjoy playing her and Fox as a way of testing my tech skill before a session or just in friendlies. I can do waveshines, shine turn around ledge dashes, etc etc with Fox but I never have done anything beyond shino stalling with sheik because I don't see its use as obviously as with Fox's tech.

I see M2K and Shroomed doing lots of weird things with needles, like turning around to grab the ledge or other odd stuff. Wouldn't a wavedash onto the ledge work just as well or is it the possibility of using backair if they recover high the point?
I guess I'm just confused is all.

 

[Etrian]

Turnaround needles is a great fast option whenever you want to use backair in your running direction. Backair is usually a better edguarding tool than fair, so reverse needles gives you acces to quickly opt between bair and grab ledge while running from the stage for an edgeguard. Also, first part of up-b wont sweetspot ledge if not facing it so you will often see players use this technic off stage even if double jump cant reach ledge. Turning around mid air as switly as sheik is not something that can easily (or at all) be acomplished by most of the melee cast so it is a great tool with a lot of intrincacies that can give your playstyle more/better options.