That's correct, but the thing is that Obanai's going to get hit one way or another. When two people are fighting, the moment a person attacks, they forgo their defenses.
Take this video for example. There's going to be times in the fight where Obanai or Kaburamaru simply wouldn't foresee Gyutaro's
Flying Blood Sickles turning around one-eighty and hitting him from behind, or small chips that Gyutaro can get off on Obanai that is simply a fair hit. Sure, Kaburamaru can predict attacks, but it only goes as far as the current knowledge they have. Obanai's Serpent Breathing is just
mimicking a serpent. I hold the opinion that it's not all that special. Both sides are comparable in skill, so there's nothing to say that Gyutaro wouldn't be able to hit Obanai even with his techniques.
Gyutaro is able to perception blitz Tengen while saving his sister in the process. Obanai is above Mitsuri in speed. Mitsuri is comparable but superior to Tengen in "technique speed." The urban environment will help up until Gyutaro decides to start using his Blood Demon Art. Obanai's Serpent Breathing does help in a desolated environment, but by that point, the poison from Gyutaro's blade would've already taken it's effect. I don't think that Obanai would be able to dodge every single attack from Gyutaro. From Daki? I agree, but when Gyutaro's summoned and
when Gyutaro gets an opening to leave the battle between him and Tengen to go help his sister, he will inevitably hit Obanai. There can be arguments made for Obanai that he will be hit later rather than sooner, but I believe that Gyutaro will hit Obanai in their second to third encounter with one another. Obanai's Serpent Breathing and Kaburamaru's
Precognition would be able to hold him over until Gyutaro starts, well, thinking and using his Blood Demon Arts. Gyutaro would tell that Obanai is blind and Kaburamaru is helping him. I think this would be possible for him because he learned how to dodge Tengen's explosives and correctly deduced the underlying motive of Hinatsuru's kunai barrage. I don't think he'd instantly understand what Kaburamaru is even doing there, but he would have a vague idea that it's helping Obanai in some way. Even if he doesn't deduce what Kaburamaru does, he'd try to kill it to be safe since he
would know that Kaburamaru is helping Obanai.
Obanai never had an opponent attack Kaburamaru instead of him, so it would be initially unexpected. Kaburmaru can be seen—at certain points—
a
He's also around his neck.
Gyutaro is capable enough to get close enough to Obanai to hit his neck area (Gyutaro decided to cut Tengen's eye for obvious reasons) He'd take that moment to attack Kaburamaru instead of Obanai.
