I have personally benefited greatly from the video obtained by a digital video camera, the in-car camera system in my patrol car. A number of years ago, I was involved in an incident where, as I arrived at the scene of a call, I came under fire by a suspect armed with a rifle. I survived the firefight, he did not. Since this incident occurred in a residential suburban neighborhood, at night, there was no one else around. Without my in-car camera, it could have been my word against the word of bereaved family members, who were not present, telling their story of woe and how their lost loved one was a good guy who would never hurt anyone. Sound remotely familiar?
It is a good idea for all departments to get these. SWAT teams especially.