The whole dynamics of conflict in Jujutsu Kaisen basically get flipped because of curse users. Most series have a neat line between the good guys using magic and the villains using evil magic. Here, it's all jujutsu energy, and 'curse user' is just a job title for a sorcerer who went freelance in the worst way. This completely scrambles the moral battlefield. It's not just about exorcising curses; it's about dealing with humans who are arguably more terrifying because they have motives, grudges, and can plan.
Take someone like Mahito's group early on. They weren't just monsters; they were a coordinated cell with Geto's ideology driving them. That ideological clash—Geto's vision of a world without non-sorcerers—is a direct, human-generated conflict that a mindless curse could never create. Then you have the chaos of Shibuya, which was orchestrated by curse users like Geto (or the being possessing him) and Mahito. They exploited the rules and social structures of the jujutsu world to tear it apart from within. The conflict stops being a simple extermination mission and becomes a civil war, with the enemy wearing the same uniform and using the same techniques.
And on a personal level, they're the ones who create the most devastating character moments. A curse might kill someone, but a curse user like Mahito is the one who breaks Yuji's spirit by forcing him to confront the reality of taking a human life and the fragility of the soul. The main conflicts stop being about power levels and start being about philosophy, trauma, and the very purpose of jujutsu society.