In game development, you will sometimes have to disable the collision between the camera and specific models in the environment, otherwise you end up with really sudden, jarring camera movements when walking around. Take for example, the streetlamps in my experience, Valencia. If you position your avatar so that the streetlamp is between your avatar and the camera, the camera suddenly gets put in front of the lamp very jarringly.
It's important to be able to disable this collision on a case-by-case basis, to prevent weird janky camera movements caused by small or thin props like this. This collision setting should be completely separate from the regular collision of the model. A model could have regular collision that blocks the avatar from walking through it, while allowing the camera to actually go through it as if there is no collision.
There are many cases where you DO want the camera to collide with props. Buildings, for example. You don't want the camera to be outside the walls of the building, preventing you from seeing your avatar that is inside. Similarly, you don't want the camera to accidentally dip inside a random building while you're walking outside in an alley way. It's better for immersion this way. So we should be able to turn on or off this collision as needed for specific models.
BTW, this is all a non-issue in VR obviously. But in desktop mode, it's an very important feature.
edit a year later- here's a screenshot sequence showing why this is a necessary feature.