User blog comment:Silver-Haired Seireitou/Revisiting Hakuda/@comment-1493741-20150516093556/@comment-2089817-20150516184703

But Z, it's also a bit strange to call Cero a non-reiatsu based technique when Bala and Hierro are, because would it not make more sense for Hollows and Arrancar abilities to follow the same fundamental concept? I know you mentioned Bala and Hierro, but you also have to concede that it sounds a bit strange for all Arrancar abilities (Bala, Hierro, even Pesquisa) to be associated with Reiatsu specifically and then say Cero is the odd man out; that it isn't like that, simply because it's not explicitly stated in the manga, but all hints and clues from the manga pretty much point to that idea. Plus, if Getsuga is similar to Cero because, as you stated, Zangetsu has Hollow origins, and yet Getsuga is a reiatsu technique, doesn't that further prove that Cero is too? I dunno, that's just how I see it. I'm not calling you wrong by any means, just that I can't agree with that.

The way I see it, Reiatsu is the preferred method for Hakuda and Zanjutsu because spiritual pressure doesn't always have to be a crushing force that smashes people into the ground. It can be very subtle as well, such as when Yamamoto scared the shit out of Nanao just by looking at her. It can take forms of mental manipulation and intimidation, elemental forms and shapes, waves of force, and so on and so forth; would you not consider that to be perfect for a discipline like Hakuda? On the other hand, kneading reiryoku and using it as it is would probably be better suited for Kidou spells. Like Void said, reiatsu and reiryoku aren't "different", per se, but simply are meant for different purposes in their respective states.