Tbh, after the whole "Hey, check out my cat!" "I don't care about you as a person, let's just have sex already" exchange, I'm kinda glad it ended the way it did. Like, I feel for Akina, I do; clearly her ex dipping out like that is going to cause some abandonment issues and need for validation, so the "well I want you to come to like me too" bit was an interesting reflection of that. But (speaking as someone who's usually a sucker for the more romantic route these usually take) I find it refreshing in this case that the outcome was so realistic; she may have "fallen for" Rikako, but did she really? Or is it just that the good sex propped up her shattered self-esteem and she wants more of that? Without coming back to the cat conversation it's ambiguous whether her feelings have really changed as significantly as she thinks, but I come away from this with the vibe that they haven't. Rikako is an emotional salve to her, not her own person with her own life. And Rikako herself probably has to deal with a lot of her clients becoming infatuated like this, and seems a deft, experienced hand at managing and balancing maintaining distance and maintaining retention with these sorts of people. (Or at the very least, didn't let herself forget that insult from earlier.)
While it could be possible for the relationship to change over time, and I would enjoy seeing Akina actually coming to see her for her, I feel like ultimately, this is a case where it turning genuinely romantic sometime down the line just wouldn't feel right; them remaining friends and occasional bedpartners but finding long-term girlfriends elsewhere feels like a good way to go. Ultimately all that is kinda beyond the scope of this oneshot, but just like, again, I respect that they didn't go the easy route, and painted such a picture of the dynamic that I can extrapolate and speculate like this, without needing to see a continuation directly. Good stuff.