What is the symbolic significance of having to play open with all types of people huddled from the rain under the portico of St.Paul’s Church?

St. Paul's Church is quaint and common as opposed to the Cathedral which is large and ornate. In the opening of the play, Eliza, like St. Paul, is considered quaint and common. It is only after her transformation that, much like a Cathedral, she becomes artificial and larger than life.