She wasn't useless because teams used her for character witness points. I consider witnesses useless if they not only offer nothing to an argument on top of holding absolutely no character points at all. I will admit she was somewhat annoying. We went against a team whose Bailey was crying profusely and I wanted to throw a pencil at her.
Any witness could be played for character, if played properly. Sure, some witnesses with the way they're written are harder to envision a character for them, however all witnesses, including experts, could be played with a character, it depends on the student, not the witness.
I consider Bailey useless because not only did she not add anything to the argument, she didn't add anything to the trial, and every trial in which Bailey testified was a trial that was brought down by her testimony, no matter the manner in which it was conducted.