Quote - The question that I have is, even you have textures and images of hi-range, the renderer is able to handle bigger resolution than 8 bits, what's the use if the final result is a jpeg image that is limited to 8 bits, or if you save as tiff or 16 bits pngs you will end viewing the image in your monitor that is limited to 8 bits. All efforts done for nothing!!!

The simple answer is that more data is always better then less data. Since the file stores more info about color and intensity then 8 bit per chan files, you can do things with it that are not possible with normal files. (some of which are described at the link posted by muralist) Also note that there is research going and even some prototype displays that are increasing the range of the screen to more then 8 bit.

Plus there is a method called 'tonemapping' which basically flattens the HDR down to normal range but preserves the detail of the HDR to give you a much higher quality image the you would get with LDR alone.