I think one area the legislation has recognized as a key area of concern, which prevents people from coming forward, is a fear that their identity won't be kept confidential. It is a key element of this.
It also, I think, goes to issues of procedural fairness for both complainants and respondents in processes like these that there is an element of confidentiality while the investigation is ongoing. It will also encourage complainants to come forward if they know their identity won't be known throughout the workplace.