The termination is not super-important when connecting a video source to a single display six or ten feet away, but once you feed a chain of several displays, each 50 feet or more apart, the proper impedance becomes critical.
Think of airport terminals in the days when the arrival and departure displays were all black-and-white. They were all fed with looped composite video in those days. One loose or missing termination (separate piece or built-in switch) would mess up a concourse full of monitors.
