A potential problem is that the officers would get an opportunity to verify and practice their story based on the camera footage, while the suspects would not.

A potential problem is that the officers would get an opportunity to verify and practice their story based on the camera footage, while the suspects would not. A prosecutor could establish that the suspect's memory of the situation is not completely correct. Meanwhile, the police officer would have a fantastic, (almost photographic!) memory of the scene. The prosecutor could then ask each about something that wasn't captured on camera. The police officer claims he saw the suspect commit the crime, the suspect claims he did not...who is a jury going to believe after that?