Then why do people get one with HDMI?
Sound+video with one cable, just as you said and a connection that is easier to connect(more easy to blind connect HDMI).
I have HDMI @ my computer but DVI on the other end of the cable for me screen(smaller plug fits better in this case.).
That said, I have yet to see any difference from one to the other(my screen seems to use a brighter profile(blue/green) with HDMI, but that is on the screen end, most likely to make movies more vivid).