"I can fix him/her!" is a very strong motivator. So is horni. Combine the two and...
As I said, I get the Doylist reason. What I don't get is why - in character, wherein the champ can't make an educated guess about plot armor - the champ would reach that conclusion or conclude that they had enough of a safety net to take that gamble.
To the best of my memory, the Aileh content is the first real crack in her armor that my character has seen that hints at someone genuine behind the corruption. Simply put, I see that content as the
start of a foundation for building bridges and reaching an understanding, but even then that's up against things like her handiwork at the Winter City and the Centaur Village, never mind the more general trail of corruption and the havoc wrought by her nominal followers under Tollus.
For the sake of illustration, let's look at the original Star Wars trilogy for a minute. Luke trying to redeem Vader and Vader actually being receptive to the effort is entirely a product of them both learning that they're family and caring
deeply about that fact. When Luke confronted Vader in the second film he was driven as much by righteous vengeance as he was the desire to save his friends from what at that point he had every reason to believe was practically evil incarnate. Luke spits "he told me
you killed [my father]" in Vader's face with raw hatred for what he'd done, and while he's initially devastated to learn that Vader really was his father, the revelation forces him to rethink everything he thought he knew. Vader was no longer some faceless evil space wizard, he was his father, someone who was once a good man. He was twisted and still acted as an agent of evil, but Luke had to believe that his father was not beyond hope because he refuses to abandon his father to the Dark Side's grasp.
Meanwhile, Vader suddenly realizes that he has someone to love, someone he wasn't aware even existed. He's not as alone as he thought, and he wants his son to be in his life. That cuts deeply into his rage, grief, and fixation on his work, and even if it didn't, the simple fact is that if he wants Luke to survive, he has to restrain himself. Yes, he thinks that the only way to get what he wants is to turn Luke to the Dark Side, but he still indulges in a more tender and proud side that had previously been absent. And that in turn reinforces Luke's belief that there is still good in him, albeit buried. And sure enough when push comes to shove, Vader chooses Luke over even his own life.
...Now imagine that the "I am your father" plot twist never happened. All of a sudden, Vader's redemption arc just doesn't work anymore. Luke doesn't have any personal investment in the outcome that would make him risk himself and everything he's fought for to save Vader, much less a reason to interpret Vader holding back as he tries to turn him to the Dark Side as anything more than a means to that end. And of course on Vader's end, Luke's just one more Jedi to add to the pile of corpses.
And that's what I mean when I say that I don't get the Watsonian reason: Pre-Aileh, I never really saw an "I am your father" moment that encourages us to rethink the trajectory of the relationship before committing to the act apropos of nothing. Yes you could cuddle up to her in the seasonal halloween picnic or knock boots with her in the dream but why would you trust that when seduction is her preferred method of corruption? The events don't feel like a change in trajectory so much as her simply trying a slightly different tactic. Yes, if we treat it as such then playing along means that it ultimately backfires on her, but
why would the champ play along rather than suspect a trap? I'm not aware of an event that should make that make sense in-character.
Rather, if anything, her relationship with Aileh and her new grandbaby is that "I am your father" moment for her, that moment that says that yes, she does indeed have a better nature and at least some principles, and that it is not in fact pointless to try and coax those out. ...Which is
deliciously ironic, considering that Aileh is only available post-Winter City, wherein you see firsthand how Kas very nearly succeeded in completely toppling the kingdom through her seductions and the corruption that came from them. Never mind how it drew special note to her disdain - if not contempt - for Alissa, who evidently believed that
she was on the Kas-Romance path.
And I'm sorry that I'm getting so longwinded here. Suffice it to say that I just enjoy nerding out about storytelling. Regardless, this content makes me hopeful that future content will again show us some cracks in Kas's armor, as those are great character moments that lower the barrier to entry for the romance path.