You're missing the point. If Boli impresses Zhuan enough, then he ends up falling under Zhuan's influence... instead of Mo's. The point for Mo here is to get people under her banner, not other people's. She wants influence over these budding crafters, not to give influence to other nobles.
Further, Zhuan Kun doesn't need this charm. Boli is selling this as "no need to find sparring partners" as a benefit... but people come to spar with Zhuan Kun all the time. He has no shortage of potential partners.
By that logic, your own vote makes no sense because Kong Zhi doesn't need this charm either. He has partners to spar with, friends to test himself against and socialize with rather than spending AP on a machine. If you're really set against Zhuan, I suggest picking someone like Nokai, who probably doesn't have the opportunity to train regularly against human opponents without facing legal consequences from Geng.
Unlike Zhi, who has Mei and Jai to beat him into the dirt regularly, and Xu Yun to duel against, what Zhuan
doesn't have is someone to really test himself against, someone who can beat him. That's why this would be valuable to him.
I've already expressed my belief that Zhuan doesn't want minions and Mo won't be offended by this, so I don't think I need to reiterate.
Remember, we've met Zhuan Kun all of once. This would be... pretty out of left field for both parties. Why not Nokai, one of Mo's allies? Or Fa, one of ours?
Because one of the major goals set for Kong Zhi by his family is to build friendships with the three noble characters in the sect. There were legal and trade consequences for his family by offending Geng, while his mother was extremely pleased with him building a relationship with Mo, and now meets regularly with Mo's mother.
Going forward advances that subplot, helps Zhi's family and makes his mother happy, and might lead to more benefits from his family in the future (though those are probably not going to top the Love Transfixed, but that's the biggest mechanical example of why helping Zhi's family is important, even trying to pay them back for that would be good and in character).
So you want to willfully betray the Heiress of a clan that uses Scorpions as it's sigil who is KNOWN for holding a grudge and fucking over those of whom she holds a grudge against? Does that sound even close to wise?
How is this a betrayal? The post you responded to was arguing that Mo will be
happy she gets the chance to network with an otherwise socially isolated noble. Even the
appearance of having him in her corner, by showing up at her tournament, would be valuable for her. She already has a dozen charmcrafters who will be eating out of her hand from the tournament. What she doesn't have is an allied social peer.