An Arakune who goes for guard breaks during a curse loop is an Arakune who has already admitted defeat.
Most Arakune players don't even learn the guard break loops because they're honestly terrible. You have 500000x more chance of mixing/crossing up your opponent, and the correct pokes will safely lead into good combos. There is really no reason whatsoever to go for the guard break (many players may spend a bit of time breaking primers then go for the mixup/crossup to maintain pressure post-curse), but it's honestly not that good. Even on a character with 4 primers, you're spending at least 50-70% of your curse time JUST breaking their primers, after which you get maybe 4k, something Ragna, Litchi, or Bang can easily get with oki and actual pressure options afterwards. If an Arakune is breaking your primers any faster than that, he either has to RC to keep pressure, which burns his precious meter, or he's dropping the loop and mindlessly using 6C/2C/j.C, and you can DP out of it.
Getting curse is way too rare and way too valuable to hedge your bets just trying to guard crush somebody. It's just not worth it. Arakune needs that huge ridiculous damage to balance out the fact that his moves totally suck otherwise. People want to think Arakune is just his old self but curse is a little harder to get and a lot better when he gets it. But so many chracters got such huge buffs (read: j.B doesn't beat anything anymore), that without curse, Arakune is a steaming pile of poop - literally everything he does is risky, and only when a risk succeeds does he get his "ridiculous" flashy curse combos. And when they fail? 4k damage combo, with oki. Arakune has a DP with meter that is ridiculously unsafe and punishable on reaction, and he has a counter assault which is worthless without 100% meter for the combo/curse, and he has a backdash which is usually pretty good, but useless in the corner (where Litchi, Bang, and Ragna will have you constantly).
Yea, Arakune's pretty imba....
This analysis is all based on your opponent having full guard primers when you start curse, of course. If they have 1 going in, maybe breaking their guard is a good plan.
P.S. Air grab is only 100% curse on low-height grab. When grabbed up high, it's 30% from cloud only. This includes the apex of a single, regular jump. I have tested it thoroughy and been very sad about it time and again.
P.P.S. Although this doesn't enter into high-level-play analysis, 100% curse combos are REALLY HARD to do. Nailing a 3-frame kara 2-3 times in one combo is no joke. It's rough.
P.P.P.S An SBO contestant and ridiculous crazy player told me that he thinks Bang is way better than Nu was. Nu at least had weaknesses, if you got in she died. Bang is amazing at everything.