I'll answer with a cliche. "The person who acts as their own attorney has a fool for a client."
Even if she doesn't talk there is still a lot for an attorney to do leading up to and during the eventual trial. At least in theory and attorney could argue in the preliminary hearing that the evidence presented wasn't sufficient to support the charges and get the charges dismissed by the judge. (Not likely, but possible.) I'm not sure whether can question the witnesses at the prelim, but at any eventual trial the attorney will be able to as well as presenting witnesses that would tend to exonerate her. She needs an attorney and, in fact, one of the big reasons (from her side) might just be to keep on her to keep her mouth shut. As the Miranda warning says, anything she says and and will be used against her.
MOO