Word Clock benefits

I wasn't exactly sure which category to put this posting as the subject matter fits in a few different areas. The question relates to the added musical benefit of adding a word clock. I can clearly see the argument for a clock with separates (a transport and a DAC). Can anyone describe the improved "imaging" effect (if any) of adding a word clock to an already fairly good player (i.e. a single device as opposed adding a clock to a transport and a DAC)? The assumption made in this is that all downstream devices from the source unit are musically good and warrant little or no consideration for change.