the lighting was not produced directly by chakra. It was real lightning created a rising column of warm air to produce a real thunderstorm. It was very indirectly created by chakra. Also, what if he fires the black flames into the sky or away from fodders or if Naruto keeps whacking Obito to distract him?
bolded: How can you not know Sasuke can produce the black flames!? In that he has well surpassed Itachi. He invented Blake Release. He's the first shown to able to extinguish them? Yeah, Sasuke can extinguish them. He did this when Karin was struck in the battle with Killer Bee.
Kirin is not chakra-formed lightning anymore than ash is oxygen because oxygen is necessary for the fire that created the ash
this thread explains it better
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