4K and 6K are pretty good. I don't play online at all, but I have seen it a good amount. Just basing this off of the two move Mitsu and Raph, I would say that those moves aren't as good offline, but they are still good.
2B+K can be alright too. It is 3 mid attacks so if your mixup has them wanting to block low this can land as well as anytime they are crouching of course. Shes got a mean anti tech game too so you could use this to add mixup to your game if you use allot of anti tech. I've also accidentally used this move by mis-keying and gotten free hits on them on the way down from launches. I need to sitdown with it and try throwing it in some combos/juggles and see if its worth a crap in that department as far as best dmg output goes. It comes out at a decent speed to note, and it has a cancel option so you could try using it as more than an anti-wakeup game move but I think there are better moves to use on your feet, and i cant remember if this is a safe move or not but I would bet my left one that it is not safe. If it is safe then it would be a nice move with the cancel mixup potential and the anti-crouch ownage but yeah its not safe im pretty sure. But nonetheless, this move is staying in my mental list of posible moves to throw out in a match.
2B+K does have that nice anti-wakeup potential though especially with 2B+K~3B...its 55dmg. The first hit crumple stuns too so it aint the shabbiest on the feet either and it does about 10 more dmg on the feet than 66/44A+B when all hits hit. and then add in the 3b and it does even more. I'm thinking 2B+K is better. I was playing with both moves in practice and they are both safe and honestly i dont see a real speed difference between 2B+K and 66/44A+B. Does 66/44A+B have any combos out of it? I cant find any. it seems to just plant them on the ground and make them uncomboable.
i tested the soul gauge dmg and they are both the same if you throw in 3b after every 2B+K. You have to do it close enough for all hits to hit though so i would say 66/44A+B is better for soul gauge since the spacing is more leniant
6K is not good. I see it as neither a good move nor a good AutoGI. The TC isn't really reliable. The AutoGI frames are very specific (it GIs verts, BTW). It's very unsafe, but it's unreliable, as the second hit will whiff on off-axis opps, and you will eat free hits.
I find that 4B+K, while worse of a move than 6K, is a better vert AutoGI cuz of its a bigger window that allows pretty easy GI-on-reaction. If you get all three hits to connect, you get stabby hops "combos" for some nice damage.
Really, though, all of her AutoGIs are kinda crap.
I agree it does have its uses. It's good against obvious canned screens. Or after having an attack blocked and you're sure the opp is gonna retaliate with a vert. I think of it as a highly risky reversal rather than a craptacular standalone move.
But I think it's something that should not ever be used in a serious match, though. At least 4K>B is hit-confirmable to a degree to avoid be destroyed if you guessed wrong...