User blog comment:Kaido King of the Beasts/Chapter 879: Mirror Battle in Mirro-World/@comment-27930128-20170922112820/@comment-27930128-20170923073617

That is so Luffy's way of fighting. Test his opponent fighting power with lower gear and later come up with an idea of manipulating opponents ability - hopefully. One that really gave Katakuri advantage is he can grow more limbs. A pair of hands for Luffy and multiple pairs of hands for Katakuri.