Maybe because that wasn't adcoc?when oda used adcoc he always draw the black lightning
Neither when Yamato used Vajra arrow
And in both cases it's impossible they didn't used AdCoC they know pretty well that AdCoA is too shallow
Even more in Luffy's case because just before that G3 he used Snakeman with AdCoC
So why will he go back for weaker attack and without AdCoC ?
Oda just doesn't draw black lightnings everytime