I messed around with this move when the game first came out, because it looks like it was clearly meant to be an anti-air for cross ups or extremely deep jump ins. Unfortunately, the move is too slow to use reliably, so I stopped using it for that purpose all together. More often than not, you simply get hit out of the start up by the cross up you’re intending to anti-air. It definitely can work, you just have to hit the cl.HK extremely early to give it time to start up. Also, it should be noted that cl.HK hits behind Cody a good amount.
I also thought there might some (costly) gimmick by doing anti-cross up cl.HK, FADC forward and be able to move to decide which side Cody would be on when they land from the reset for a good mixup. Unfortunately this basically doesn’t work. Like I said, the most effective use of the move is to anti-air cross ups. The thing is, due to the slow start up of the move and the hitbox extending behind him, when you anti-air a cross up, Cody will almost always wind up hitting them after they’ve switched sides. Therefore, when you try to FADC dash forward, your dash will get auto-corrected and you’ll dash the wrong way. This sounds like a weird random thing, but it happens extremely consistently. To dash in the direction you’d want, you have to input an FADC back dash, which will get you an auto corrected back dash in the direction you want, but of course, Cody’s back dash is too shitty to give you time to position yourself on the side of your choosing.
tl;dr: I use it very rarely, and only for a very obvious cross up jump attempt. Mostly, it’s too slow to use on reaction for crossup/deep jumps because apparently, it’s the only thing in the game slower than his walk speed.