Odd struct in material.h

In material.h, there is a struct

struct StageData
   {
      GFXTexHandle      tex[GFXShaderFeatureData::NumFeatures];
      GFXCubemap *      cubemap;
      bool              lightmap;

      StageData()
      {
         cubemap = NULL;
         lightmap = false;
      }
   };

Why is there a GFXTexHandle for every feature when only a few features are textures?