Mainly, it is for convenience (actually, on the 1050 that's the exclusive reason, as there is no OSD). Let's say your TV has a single video input (as was true with the TV I used with my old 1050). You probably have more than one video source - DVD player, VCR, cable box, game console, ... You connect the video output from each device to the associated video input on the 1050 rather than running to the TV, and you connect the 1050's monitor output to the TV's input. As the 1050's active input changes (DVD, Video1, ...) the active video input is passed to the 1050's monitor output and on to the TV's lone video input. Even when you have more than one video input, this scheme can simplify the user interface by allowing a single act - selecting the input on the receiver - to set both audio and video to the correct source. That can make it much easier for family members who just want to be able to watch TV to use the system.