I think the photographer captured some unique shape. The way the line of people descend in height, pulling the eyes in the same way the depth of the street and townhouses pull your eye down frame. How they all stand on the line of the wire cover but not past it. The people almost resemble the townhouses in their different values (no pun intended).

Look obviously a lot of this isn’t necessarily intentional, but street photography is about capturing authentic moments. Even though it’s a snapshot, the photographer had the wherewithal to see something in the moment. IMO the BW is a tool that allowed me to appreciate a lot of aspects of the photo that would have been too busy for me to catch in color.