While it is incredibly depressing and heartbreaking to see, we can now see how that Jiraikei girl Yua got into selling her body to old men in order make enough to cover costs for that bullshit overpriced champagne run at the host club.
Once you start craving the validation and affection of the hot ikemen, it's a downward spiral. All those hot guys have to do is simply treat them nicely with patience, and they know that one day, even a girl jaded with pessimism like Moe-chan will crack.