Whether he did or didn't isn't very important in my opinion, because Kizaru was blocking all of his attacks and we already saw him block Luffy's kick with ease, which did produce lightning.
I will also add that there is already a lot going on in that panel, especially with Kizaru's light effects, and adding lightning would create a lot of visual noise and make for ugly art. Once fans start looking at haki from an artists perspective, suddenly Oda's choices make a lot more sense.
20 years ago I would have believed this. But modern Oda since WCI has crammed so many panels into few pages and condensed so much stuff into double spreads that I don’t believe he thinks about for aesthetics unless it’s a major reveal like Gorosei and Shamrock/Gunko
He basically skipped Kizaru vs G4, so either 1) Luffy didn’t use CoC as visuals indicate, 2) he used it and we have to assume every haki moment is also a CoC moment. Luffy admits he goes ALL OUT when he fights so yea
It would just make so much more sense if ACoC had a hidden deadly side effect that not even Luffy would want to keep spamming