Bin is practically a carbon copy of her mom, but I don't know why I don't find her as beautiful as Chowon. Maybe it's because of the hair, or perhaps they just have different kinds of appeal. Chowon has this certain vibe that makes you attracted to him, even though he has a pretty shitty personality.
Chowon has a higher charisma stat because he has a mastery skill level. Bin has nothing to back her up, she knows it, and it comes across as someone trying to make up for lost ground.
Never forget that charisma can change the whole picture. For example, Jack Black is not who people think of when they think of a megastar. But even if you didn't know who he was and what he did for a living, he has enough confidence in what he does that you would find yourself agreeing to a lot of what he asks. There's also a woman who looks like a church mouse but it came out that she was dating six millionaires at the same time.
Some people are born with high charisma while others get that boost from being the best at what they do. Without it, Bin's looks only open the door and it shuts with her mouth opening.
I like me some smut with a good plot. Can't wait for the next season