Mechanically that's all true, but narratively there's more to it than that.
The QMs have said that leveling a social stat doesn't change a character's characterization.
My reading of the situation is that Kei wants some actual social skills that don't rely on lying to or scaring the shit out of whoever she's trying to have a constructive conversation with.
Social stats are for social combat, not two people having a good faith, constructive conversation.
She's also a big girl and can tell us how she feels, if that is the case. She hasn't, and she's nit shy about letting us know how she feels. Since she hasn't, I'm discounting this.
Also, deceit and intimidation aren't the right skills to a) do so e serious diplomacy with an ally one had a difficult past with, b) reconnecting to any extent with old family and friends, or c) manage either the KEI or her own polycule with more than stubbornness and luck.
The Mori aren't allies, nor are her biological family members (Ami exempted).
Kei manages KEI just fine, as-is, and the only reason she would need to roll social stats against her own polycule is if she were in social combat with them. The Kittensphere is healthy enough that I doubt this will ever come to pass.
Kei repeatedly claims to have no idea why so many people seem to like her or why her attempts to get people into any specific emotional state or position of understanding even works out. Part of that is narrative too (as is the part where so many of her social projects work out in the first place), but if nothing else then numerical social skills still represent formal training and understanding.
Vel has repeatedly asserted that the playerbase should be grateful that the QMs to not have mechanical socials stats influence narrative characterization.
Discounting this.
Kei could finally be able to better analyze what the hell she is doing and what effect it actually has on others, for good or ill.
Kei is already doing better, without the need to screw up her build with sub-optimal social syat investments.
Sure, she's not perfect, but she's at a much better point now, than she was at the start of the quest. Does she backslide on occasion? Sure, but healing and growth aren't linear.