What is the importance of "overcoats" in the story, After Twenty Years?

In contrast to the details that make Bob appear like a suspicious outsider, the overcoats worn by nameless, faceless pedestrians and tall plainclothesman symbolize anonymity and conformity. Once the rain brings the streets suddenly to life, the narrator mentions how everyone puts up their coat collars and their hands in their coat pockets as they raced home. It thus seems as if the overcoat is a staple element of the early twentieth century male wardrobe. With the exception of Patrolman Wells and Bob, all the other characters in the story wear similar coats. The tall plainclothesman in his long overcoat emerges without bringing attention to himself, and it is his overcoat that allows the plainclothesman to remain mostly hidden from Bob's scrutiny until the climactic moment of illumination.