the major advantage is vandal protection, indoors they are often well within reach.. and indoors the criminals have more time to try to disable the cameras, plenty of video captures of even the police trying to knock cameras down.. a turret for example someone can just reach up and turn it so it faces the wall.. a dome your going to have to knock completely off the mounts and its going to record your attempt much longer.. if you can continue recording while someone is trying to disable the camera, you often get the best evidence.. because they get so up close and personal with it.
the only dome I have is in my kids room, and im glad its a dome because he's made contact with the camera more than once tossing stuffties and toys around.. anything other than the dome he would have changed the FOV with a small impact.