Why does the author not describe Chris Watters physically?
I tend to think that Chris' function in the work is more as an ideal. He represents the ideal notion of love, partnership, and a sense of devotion. Chris is not someone that is of the real world. His function in the narrative is to provide that sort of idealistic end to which our feelings of love always pivot towards, a sort of undefined longing that captures our heart's imagination. Certainly, he does this for Edie. It is for this reason that when he tells her to "wait," it is significant. Edie's waiting for Chris is an exercise of how the daily reality of life can become paralyzed by the condition of waiting for something that is not real. It is for this reason that Chris is not described in real world detail. He is articulated in terms that are idealistic, not of this world. In not describing him physically, Munro is able to retain the idea that he is an ideal, someone or something that is not attainable in this life. As opposed to this vision, the mailman is someone real, definable in this context and valid in terms of how reality is to be understood. In this light, one sees how Edie moves from one trapped by the condition of waiting, someone whose epiphany reveals a movement away from ideals that might not happen to a realistic and workable vision of living where reality is understood for both what it is and its potential for happiness:
...if there were women all through life waiting, and women busy and not waiting, I knew which I had to be.
In this, Edie's epiphany helps her understand reality, and move away from the ideal of Chris, never described as something physically real, but rather as illusory and not of this world.