Thats why you use it in situations where the opponent is limited in his options, so mainly on oki.
I personally wouldn't use it for whiffpunishment because it doesn't deal any dmg on NH. And again, i am thinking you are getting deceived by it being i42 - you can at least distract 10-14 frames from that due to the QS frames and the faint. This move rarely gets blocked. As a rule of thumb, if they cannot block 1A consistently, they won't be able to block 22ka:2A consistently.
You use that move mainly in oki situations, when you would otherwise only mix up between the tip of 2A and a mid like 3B. However the benefit it has over 2A is that instead of being -4 (which means your pressure ends just there) its +2 which means you can either press the offense further or mix them up again. It also hits grounded, catches rollers and movement too and in case they were going for a slow wakeup attack they eat much more CH dmg then 2A would have given you. Unsafety is also usually not one of your concerns at its tip (its -15).
im gonna assume you meant 1A here because 2A isnt really anything like 22_88ka2:A on hit.
its 10 frames added by quickstep, but even then the animation itself is still i32, and that is very very slow. rather than getting a move blocked on oki, i would rather get a shot at some free damage or a mixup. you may have enough frames for the move, but that doesnt mean it will be anymore effective. its a slow reactable low no matter how you look at it.
as for whiff punishment, the reason i listed that is because it would at least be functional in that situation. of course in that situation, like many others this move can be used in, siegfried has better options he can resort to anyways.
if they dont block 1A consistently, then they deserve to eat 22ka:2A. but if they've got a little bit of experience, there shouldnt be a reason why they cannot block it on reaction.
and in oki situations i would go for 3B/1K as 1K also catches rolling and is much faster than 1A. and well 2A doesnt even hit grounded, just incase you did mean 2A.
and well the move is reactable in oki - because siegfried lacks anything truly threatening in oki, i could just lay there and block the 22_88ka:2A. honestly i really think you're better off hitting with 1K and 3B - that way at least you're far less succeptable to silly things like wakeup CE's, because you are going out of your way to lockdown your oki frame advantage wise. whats most important oki wise in this game imo, is making your opponent respect your frame advantage on oki - less they get away with murder. afterall when our opponents dont lock down oki vs us, look at the damage siegfried can do with WR AA/WR B, and look at what wakeup CE's can do if you get greedy or you're not careful?
