I would imagine it would be probative for the defense to bring in evidence of every data breach containing her name and ssn. I don’t think pointing out how common these data leaks are generally would be of direct evidentiary value to the case, though.
Of course it would. Most jurors have probably received more than one "We take security seriously" letter and free credit monitoring because they were included in a data breach. Relating to their own experience and getting them to think "that could be me" about the defendant would be very valuable. Creating reasonable doubt is the primary job of a criminal defense attorney, as that obligates the jury to a not guilty finding.