I agree with Rocky, there is something cathartic in being believed, it being accepted what happened, that it was wrong etc... I feel that there can be a lot of negative and skewed thoughts over what happened, depending on the circumstances, confusion over blame, feelings of guilt, the whole dirty secret issue, it rebounds some of the evil of what happened back on the victim.
I think the fact that it was in a time when things like that weren't talked about so much, buried and kept quiet and the subsequent knock on effect on the victim can do a lot of damage in its own right.
It will never disappear but something is better than nothing when you're living with a life sentence of the after effects of abuse. It could be a useful stepping point for people to move on from, get help, accept help, be more open about it... Acceptance is a big step in itself.