I mean, otherwise the scene was just pointless all around, iirc was the first time the MC and her meet and the whole update was filled with sex scenes...
Yeah, it was all pointless.
I say the following with the utmost respect for Buu. I've worked on AVN, and I know how much work goes into it.
It's fine to take inspiration from or pay homage to other titles. But shoehorning in some twists or reveals doesn't work and even risks diminishing the original work. The Virgin Queen reveal of Tales From The Unending Void worked because she was the MC's sister. Its MC had made significant sacrifices to find her, and we learned how the Amazons treated off-world men and women, creating some anxiety and tension on top of having lost 6 months of time. We were invested in her, despite only having a few scenes together, because the MC
showed us how important she was to him.
The similar reveal in Nephilim falls flat because we don't care about the diplomat. She's a stranger without an actual importance to the story. The sealed scroll is more important than her, making it even less important that she's alive, let alone the ruler of the 2nd village.
Brenda's story suffers from the same issue. The stakes are raised because of her conflict with Pearl and Kira. Brenda then tries to make amends with Kira, but we don't know if it's because she knows what's coming or if she's genuinely remorseful. Kira just tolerates her, so we never get the impression that their conflict is resolved; nothing happens to the stakes. Brenda coming on to the MC shows that she's jealous and has no regard for Kira or Pearl. She wants what she thinks Kira and Pearl are getting from the MC. This is a fakeout that only kind of works because the reader is trained to believe that anyone we (can) fuck is immortal. The player might be surprised, but I doubt anyone playing was feeling anything for Brenda. Unlike the death of a side character in AVNs like The Neverwhere Tales, the player never had a chance to get invested in Brenda's future. And it's clear from the way Nephilim lingers on Brenda being pinned to the wall that Buu wanted this scene to have an impact. Sadly, it didn't, because we never got an opportunity to grow to care about Brenda.