Only people within each skill area know the full extent of information they need for most effective execution of their responsibilities. They should have access to whatever they consider they need. (If there is a perceived problem with confidentiality that is a separate issue to be dealt with by other means).
In many cases, superfluous information can simply allow the person to feel more connected to the project and therefore more motivated. The more open the communication, the more likely it is that those in need of information will get it. It is dangerous to rely on specified channels and need-to-know only information flow.
Knowledge is power and the more project team members that have it, the more empowered and successful they will be (“Shared knowledge is more powerful than individual knowledge”).
