Its weird i thought about that myself but i dont know how to feel
At one hand the sanji elbaf chapters confirmed, and the lack of totally visual indicators always indicated, that in those feats no haki was involved, or atleast no CoC, like i always believed so it confirms my thinking
At the other Hand where is oda going with this no giving sanji coc coating which if properly applied can used as defense + even eventually future sight, given there was such an emphasis on in it egghead

I don’t think the fact that they were no visual indicators proves that it isn’t Haki related just coz when Zoro manifested it the first time against Kaido, there were none. That said I’m leaning more in the direction of it not being Haki per se. As there is a strong indication that it’s a unique ability of the Buccaneers which would explain why Kiz couldn’t wrap his head around Sanji decimating his laser.
For a while now I’ve been thinking that it’d end up being more of a medium for pushing Sanji’s Haki to greater heights where he’d have probably not been able to reach other wise.
Let’s say Sanji puts up regular CoC barrier, he might be able to tank an El Thor but PoL allows him to be able to tank something like an Amaru or maybe a Raigo for instance.
Been saying it for a while now folks that are simply content with CoC and are completely ignoring PoL are missing the forest for the trees and personally I’m glad Oda isn’t.
Sanji simply having CoC coating is lovely and all but how does that separate him from the likes of a Yamato for instance?
With Luffy he’s the MC, he is also Nika and has Shanks as his floor Haki wise & we know how ridiculous those two are.
With Zoro, Oda’s emphasizing the sheer volume he has which I think is prolly connected to Enma somehow in that Oda’s using Enma as a tool to really have is Haki grow & prove to be something else. (of course Zoro’s sheer force of spirit is something that’s been emphasized for a while now so prolly isn’t just Enma)
In that sense I think PoL will be Sanji’s X factor.