"Pivot walking", and has been around for a while.
It's also completely useless though.
Entirely untrue. Pivot walking opens another avenue of edgeguarding to characters who otherwise have a rough time through the slower technique of Wavedash-to-ledge. It's also much safer, in addition to being faster (no risk of accidentally airdodging off of the stage and killing yourself).
Moonwalking can act as a faster, safer alternative to wavedashing to the ledge for characters like, say, Link, who lack a fast-acting Wavedash. For characters, however, that
lack that option (Bowser comes to mind), the pivot walk can fill the roll nicely.
In terms of speed and safety for advanced edge-hogging techniques:
Pivot Walk > Moonwalk > Wavedash
Everybody can pivot walk, though it can be slower than moonwalking with a weaker range, moonwalking is quick, and doesn't pose any risk of accidental airdodging on air, and wavedashing to the ledge is probably the slowest option between the three.