Sorry what's the camera for?
Evidence in the case of an incident which ends up in court. I get the impression some cyclists cycle in areas where drivers are particularly antagonistic, aggressive or incompetent, so a camera may be useful for evidence in road incidents where there are no witnesses. A camera can also be used as an educational tool, for example if I have a close encounter I can look at the footage afterwards and assess whether there is anything I could have done better. I haven't felt the need for a camera yet as I am fortunate enough to cycle on roads where drivers are, in the main, co-operative and reasonable.