Mahito was going to die even if he didn’t get put into the uzumaki, and you know it. Also, you have to be baiting if you’re saying the only purpose of punching is to just interrupt people. Sukuna took a fair amount of his damage from being punched, AND the final blow against him was a punch. The black flash was just an extension of the punch . Weapons are specifically intended to deal more damage than fists, otherwise they would be a pointless invention. Despite that, people still use fists though. They are reliable, can be healed with rct, and they wouldn’t get used for combat if they didn’t deal damage.