IMO, Luffy is so far ahead of everyone else, it’s not even funny. Being able to use G4 alone made him physically superior than any non-top tiers. So being able to casually turn it on and off without major drawback is a huge boom. Let’s also not forget his mastery over flowing haki and later penetration. That boosts up his ap even in base to much higher levels. And knowing Luffy, he would definitely create a new form/technique that takes advantage of his new CoA abilities, much like how G4 took advantage of Hardening.