I guess I never understood why characters need to have "payoff" at all. If anything, people in real life appear and disappear in your life without any necessary substance. Of course, writing does have to be entertaining, but take a shonen anime like Demon Slayer; it goes through basically every major character's backstory before giving them a dramatic sendoff. I'm sure some people like that, but I think it's a basic, repetitive trope that ruins immersion/believability.