Even though she's a bit bland, she can be funny sometimes, like in Stupid Spoiled Whore Video Playset and Bebe's Boobs Destroy Society. She's also cute and doesn't act like a brat like Wendy. I love her hair, by the way.
Like all the other girls in South Park (Except Wendy), they are all bland and have no purpose other than being the side of the other gender. Bebe is not only bland but looks like a whore in my opinion.