I think the role of speakers like Brand is to change prevailing paradigms of collective apathy and powerlessness and instil the belief in people more generally that something can indeed be done. Every movement needs charismatic motivational speakers for people to get behind and provoke action. Folks who chat in pubs don't garner the same kind of audiences that celebrities do. And while I loathe celebrity culture, when individuals who decide to use their position to speak about things that matter there is a power in that. One that the PTB don't like too much as the assassinations of figures like Diana and Lennon attest to (yes, I tend to think they were assassinated for being inconvenient trouble makers)