The police body cam that is worn by your local officers is something that records interactions between law enforcement and the public. The purpose of having this worn by the officer is to make sure that everything that happens between that officer and the members of the public is accurately recorded for the future.
This is a very small device that they literally wear on their uniform. These devices are also extremely important to make sure that the interactions that occur between police and members of the public are kept accurate.
This kind of thing can be recorded so that it might be used for the records that go into court. The police can use these videos to help understand what happened during a particular interaction between themselves and the people that they interact with.
The public also appreciates having these details out in the world so that they can see what law enforcement officers are doing on their behalf. That is a huge deal when you are looking at accomplishing the process of telling the truth about what happened in a particular interaction between law enforcement and those that they encounter. That is the best way to keep everything straight.