After using Vine, when the Vine either finishes pulling Ammy or is cut via Power Slash, Ammy is placed in an airborne state with some unique properties. Principally, Ammy retains her ground jump, double jump, and air tackle if she had those before using Vine. The air tackle can be cancelled into a wall-jump if Ammy hasn't used a double jump, which is not normally possible. This can be seen during Cookie Clip. If Ammy hasn't obtained double jump, she can sometimes wall-jump in mid-air after Vining to inverted flowers, though the exact conditions for this aren't known.
Vine Jumps can be used to gain more height than is otherwise possible. This is used in NG Wawku Early, which uses the initial upward boost of a long-range vine twice, along with an aerial ground jump and double jump,to barely clear an invisible wall in Ezofuji.
As this glitch requires well-positioned flowers and limits Ammy's horizontal momentum, there are no other currently-known useful applications.