That move is one of my favorites in the whole game.
20 frame mid that is -8 on block, gives +17 advantage even on fastest SE and causes the critical burst.
Imo one of his best spacing tools too, due to the fact that it has a delayable follow-up that has to be respected if one does not want to eat a sitdown stun (or how this kind of stun is called) which leads into even more advantage for Jann.