I'm not sure taunt helps much at the start, maybe a tiny bit. But later, oh, it helps a lot. Along with a dash upgrade, it let me skip a bunch of stuff. Just jump and tap taunt instead of holding, Vernal does a flip and gets a bit it height and, if moving horizontally too, some momentum. You can't really change directions very much after doing it, though.

wait how does the taunt helps ? inst it just for looks ?

Nice, never noticed that one.
A few more obvious ones for gaining a bit more manoeuvrability:
- Charged uppercut (up to 2 with memory)
- mid-air taunt attack (sideways or diagonally up)
- mid air taunt can give a teeny bit of help at times
- well timed continuous sideways slashes can give you a ton of horizontal reach
I love that the game has all these put in, you can get many upgrades much earlier than you'd expect.