Not just because he photographed war or consequences of pollution, or people's sufferings. It was more than that. It was about capturing a moment that lasted a split second and under no circumstances could have been repeated again. It was about conveying a message through a stunning image that evoked emotions.
The very first photograph of Smith I saw was the "Walk to Paradise Garden"(1946) - single photo of his two children walking hand in hand towards a clearing in woods. And I was blown away by the power of this image. Not only Smith creates visually strong images, he creates a mood, he tells a story with it. And that's a sign of a truly great photographer.