Er, it's not the lighting, but more the shaders that are used for metallic surfaces.
Specular highlights are a cheap fake for reflections, developed in the early years of computer graphics. They have various disadvantages, like uniform color, size, precision - they'll always act like a small, circular light source.
In reality, you won't only get reflections from light sources, but - with varying intensity - from every bright surface, or for example from the entire frame of a window to an overly bright outdoor enviroment. So you'll get reflections of various shapes, sizes and intensities; this is where HDR images and rendering come handy too.
The first game that has really made use of this approach was Half-life 2, where a lot of reflection 'spheres' were placed on the map; that is, enviroment textures that were used instead of specular highlights. The texture has contained a version of the enviroment with pre-adjusted brightness, because there was no HDRI support in the original version. Metallic pipes, tile floors, even antlions and some enemies have used these textures.
So, HS seems to be using this approach as well, but probably with HDR reflection maps instead; but the lighting is cool as well