Because it's not a camera case first and foremost.
Its really not a huge inconvenience to take pictures, adds maybe a second or two to the over all time. And if that is too long to snag that impromptu photo, you must walk around with your phone out and camera open at all times lol
And when looking at the little black book, the strap runs right across the camera opening.
@allie, it (the LBB) really looks like a thicker moleskine book when all closed up..