It's a benefit for both ways I think. Policemen could have proof of bad behavior from people claiming abuse of force and people could get proof from the same but reversed.
Also knowing that policemen have cams on all the time, it would discourage more people from acting like thugs because they know they are filmed. Same as policemen that want to abuse of their power, they would think before jumping on their guns.
I think the only ones who would be agains't this are those who take benefit from the current situation. Cops supremacists and weapon sellers that wanted the money to be put in the militarisation of the police force.








