Because some of us are bored and we like talking about our characters' relationships.
We all know how these work, right? Comment with your character, and other characters will respond. Then you tell them what their character thinks of them! Planning for future CR or discussion can ensue~
Bonus points: Social links!! If you feel like it, pick a major arcana card to represent each character (survey here if you prefer the internet to pick for you) and give a value of social link from 1-10. 1 for acquaintances, 10 for bff/family/etc; "reversed" if you don't get along!