The NSA recording your Skype calls has no tangible consequences. An official police camera recording an officer's misconduct can cause that officer to lose their job or freedom. I don't think they'll forget, and even if they do, the bad ones will get ejected from the force.
I agree, with the caveat that this will only be effective as long as there's some kind of penalty for the camera getting turned off or 'breaking'. This seems to be a recurring theme, wherever they get deployed. One example is the police killing of O’Neal in Chicago in July. The officer involved there had his camera turned off. This might have been an issue with training the officer with the equipment, but it's hard to truly know.
A separate issue is that these body cameras need to be deployed universally or they lose credibility and effectiveness. One example of this is Korryn Gaines' death in Baltimore in August, where there is some question of whether the police were wearing bodycams during a raid after a 7 hour standoff at the woman's home (she was armed). The police wouldn't confirm there were any bodycams present until a photograph was found which showed a bodycam on one of the officers at the door to the woman's apartment at some point during the standoff. The police claimed then that none were present for the raid, and only a few support officers outside were wearing them.
The problem here isn't whether they were or weren't wearing the cameras in that particular incident, or whether there was anything suspect about the police' performance there. The problem is that it is completely _possible_ for the police to cover up events that the bodycams are supposed to provide accountability for by simply refusing to admit that there was a camera in use until someone shows up with a photograph. I don't believe that's what happened in that case, but I do think it's plausible that some police department will eventually do this to avoid public scrutiny during some embarrassing or controversial event.
I'm not really certain how we could make police accountable, in a fair fashion, for instances where the equipment legitimately fails. I think some penalty here should be on the department instead of individual officers, but I'm not sure what that punishment should be. Equipment failure in the field isn't unheard of, but if checks are performed before going on duty and there is regular maintenance, then it should hopefully become a rare occurrence, and even more rare for it to occur during an event where such a record could provide substantial testimony to the police's behavior during some situation. I'm sure the tech isn't completely stable, yet, but solid reliability needs to be one of the highest priorities for any such program.
The camera should directly upload footage to a server that is not owned by the police but a different branch of government that does not have any incentives to shield the police.