When we play PvP, we want to have fun competing. What better way to enjoy your success, than to see a slow motion kill of the last kill of the match in all its glory? Essentially, the last kill would be glorified so as to drive home the winning team's victory to the opposition. As soon as the last kill happens an instant replay would take over everyone's screen and force everyone to watch it, unless you hit x to skip and proceeded directly to the postgame lobby, making it optional.
However, it would let the winners feel more like a legend. Great idea, no?