Contrary to what a lot of people think, HDR photography stands for High dynamic Range and not High Definition Range photography.  High-dynamic-range photographs are achieved by capturing multiple photographs using exposure bracketing, and then merging them into one image using special photographic software.  This process is known as HDR imaging and is a intensive hands on human process.  The camera's 'raw image' format is used because JPG photo format doesn't offer the sharpness of a raw image which is best for the HDR process. Photos taken in JPG format introduce an undesirable lossy compression effect which loses detail in the photo.  With HDR, each photo has to be individually manipulate to adjust the best parts of the exposure of each of the multiple photographs that are taken.  This can only be achived by someone who specializes in the art of HDR manipulation.  This specific skill set and the aspect that each photograph has to be manipulated by a human are some of the reasons why HDR images carry a slightly more higher cost. However, the results are significantly better than standard photography.  

With HDR photography, you will be able to see what is outside of a window instead of seeing a 'whited out' window or whats known as 'window blowout'.  This is what normally occurs with standard photography.  Also with standard photogrpahy, the light that comes through the window may make the rest of the photo appear as though it were 'washed out' due to additional light from the window. 

HDR images are sharper due to the fact that the original images are taken in RAW format.  Color accuracy on a standard photograph is considerably less than HDR photography as only one exposure is taken for standard photography.  Because of this, colors in the photos (walls, flooring, furniture etc.) can be effected by the light conditions in the room at the time that the photo is taken.  This means that colors may appear brighter or duller and not as true of a representation of the colors in real life to the eye.  With HDR, because of the fact that multiple shots are taken with various exposures, the resulting photo can be manipulated to produce a much more 'color accurate' photo.