Honestly it's really not that deep. It's human nature to win using a little strength as possible because it's more of a challenge. Y'all are reading this thinking "why not just go all-out" but you're being way too logical - this is what competitive people do, they handicap themselves to make things more of a challenge.
Hell I do it myself. If I'm playing FIFA with a friend who is trash at the game, you think I'm picking my best 5 star team? No, I'm picking some shit 3 star team and giving them the best team in the world to make it more of a challenge. If I struggle to win y'all would say "well why not just pick a 5 star team and stomp" but that's no fun at all. Easy wins are boring as shit.
Luffy and Zoro are two people who enjoy battling - why would they wanna stomp everyone out in two seconds with ACoC? When shit gets serious, they'll get serious - it's that simple.
Though to answer your question, Zoro is so dumb that even Luffy thinks he's dumb. But his battle IQ isn't bad.
Hell I do it myself. If I'm playing FIFA with a friend who is trash at the game, you think I'm picking my best 5 star team? No, I'm picking some shit 3 star team and giving them the best team in the world to make it more of a challenge. If I struggle to win y'all would say "well why not just pick a 5 star team and stomp" but that's no fun at all. Easy wins are boring as shit.
Luffy and Zoro are two people who enjoy battling - why would they wanna stomp everyone out in two seconds with ACoC? When shit gets serious, they'll get serious - it's that simple.
Though to answer your question, Zoro is so dumb that even Luffy thinks he's dumb. But his battle IQ isn't bad.