Lol, are you for real? no one, literally no one thought they would do that much whatever they did against Kaidou before Oden flashback. It is not that they were made useless, it is that Oda made them more than what they are. Reread Dressrosa and Punk Hazard, you will see how much boost Kinemon got. Basically, scabbards got more wank than any other arc side characters. They fucking got to fight an admiral. Literally, this work and till now, straw hats are looking more like side characters than main characters, and this manga is more like samurai manga than pirate manga.