genetics play 40 to 65% in the temper of a person. If for example, one of your parents is quick to get mad and explore to others, there's AT LEAST a 50% you'll be born that way. ALSO, studies show that the LACK of positive bonding between a parent and their kid is one of the direct causes for an aggressive/antisocial conduct to develop.
Bin matches both. Genetic factor, sure, she's lit Chowon's daughter in the good and bad sense of what that implies hereditarily. Then, Chowon is emotionally avoidant of her, adding flue to an already prompted to explote kid

Why make Bin a Cho won doppelgänger in personality too? She was raised by Kyungsoo, shouldn’t she be a little more like him?