Its a cop out man. If a chick can't tell you WHY she cares about you, its always a huge red flag. Means she's hiding the truth from you, she'd rather not tell you because she knows its wrong and she would be exposing herself.
That also is both ways, usually its sex for a guy though, or at least it has been for me lol, but I'm straight up with mines, no tom foolery like this chick.