I have completely changed my perspective on Katakuri, he is so funny. HE GOT THE SCARS BECAUSE HE ATE TOO MUCH, it's so good. And the fact that he can see all the shit everyone's about to do and is secretly freaking out the whole time is hilarious.
But when you look at him as a standard arc miniboss, rather than the "Almighty solo-king" his fans hype him up as, he's a really good character. He's just like Luffy, and everyone knows that, but the thing is, he's a Luffy that had to be serious all the time. He likes Luffy because Luffy is everything he wants to be: Free.
Katakuri hides behind a "cool" shell in a detrimental behavior, attempting to put up a brave face, to inspire and protect his family, and I think a lot of older siblings can relate to that.
Also, I like to imagine that before Whole Cake, Zoro was thinking "Damn, this is gonna be a Sanji arc, and I'm not there to steal the show by being equally cool? Shit, what do I do?" and then a couple minutes later, he accidentally runs into Brook and goes "Alright, so I know I won your big fight in Thriller Bark, but you have the chance to do something hilarious."
The combo of these posts is funny because there's a bit where Katakuri goes "You seem to be quite powerful, skeleton," while leaning back against the mast of the Sunny, and Brook goes "Well, I'm the Soul King, after all."
Furthermore, Katakuri's Future Sight is a really good plot point for another reason I forgot to mention. He's the first big enemy post-timeskip to not underestimate Luffy.
Allow me to provide an example. Doffy made a big deal about how he didn't underestimate him like Crocodile or something, but then he saw Luffy, who to his knowledge had 2 significant transformations already, transforming, and went "you got bigger I guess, whatever," then the moment he saw Boundman jumping around in the air, he went "Is this a joke? I thought you had a plan. You can't even stand properly anymore," and, the when Luffy started explaining that treating him like a joke was a mistake, he thought it over for a second and went "Ok, you're more resilient, but what's that gonna do?" And then Boundman massacres him.
Meanwhile, Katakuri sees Luffy coming in his direction. Two of his crewmates just got beaten by Perospero. Luffy's flanked by, from his perspective: a random Mink warrior, a guy who he knows can fight on par with Tamago, a woman who can control the weather, and a former WARLORD OF THE SEA. They're all getting chased by Big Mom, and at one point, Luffy's got his tongue hanging out like a dog while he does it. Katakuri knows. He looks around at his group, including, as I mentioned, Perospero, who took down a weakened Brook and Chopper effortlessly, and he points behind him, and looks directly at Luffy.
"Return to the Mirro-World. Within mere seconds... you'll all be lying at his feet."
