A partner who constantly needs compliments and validation but won't commit is using you to boost her ego. You deserve a two-way relationship where both people are actually invested, not a one-sided arrangement.
The next sign that she's just using you is that maybe she wants a ton of validation, but a relationship never really goes anywhere. She wants the compliments, she wants to feel awesome and cool, but a relationship just never really gets off the ground. There's never any commitment. Instead, it just kind of feels like you're there to validate her. If that's what it feels like, well, that's possibly what it is. And you, again, you deserve a relationship that's give and take, that's two people committed and proactive about this. You deserve someone who truly cares about you, and not just about how you make them feel because they need an ego boost.
