I do it. My wife does it. My sister does it. The cameras at Bloomberg all had shutters, and I used it there as well. It's just good (paranoid?) OPSEC to defend against remote takeover exploits.
It doesn't, obviously, and I never said it did. It prevents the camera from being used to surreptitiously record useful information when a machine has been remotely compromised. It's the same reason nothing with a transmitter is permitted in classified areas without specific authorization. Preventing a remote takeover is effectively impossible, but these steps reduce the usefulness of such an action (which is part of the defense against them).