But he just randomly pulled it out against Lucci in a gag panel
in fact there was another gag panel in Wano with him fighting Sanji where he pulled it out
CoC isn’t treated as a big deal to Zoro if he’s using it gags…
somehow 600 chapters later Zoro’s big deal power remains Ashura… Ashura is the only thing that Oda explicitly reserves and doesn’t want anyone to know whether Zoro can just use sporadically
I don't see why he can't pull it out in the heat of a fight, like he would do with cutting steel preskip.
The thing here is, Zoro is using CoC in a different form than he is accustomed to seeing it. If he's never seen it done before, then how does he know what it is he's using? It doesn't make any sense for him to know exactly what it is, because he hasn't had anyone around that randomly passed out while he used it, which is what most people attribute to Conquerors Haki.
There is also the fact that during the fight against the Seraphims, he never once used it, nor suggested using it, despite knowing that it was somewhat effective against King. Instead he pretty much said that there was no way for them to cause damage to the seraphim, despite there actually being a way.