[Samekas]

No - what sense would that make?

 Because it's already matching the source refresh rate at least with auto refresh rate change working. So I don't see the point of v-sync.

"Short for Vertical Sync, Vsync is a display option found in some 3-D computer games that allow the gamer to synchronize the frame rate of the game with the monitor refresh rate for better stability. If theVsync is turned off, gamers might obtain a higher frame rate but this action may introduce artifacts in the game."   

 That's one, very specific and narrow, definition of V-sync.  

The more widely used one is used is the technique that is used to ensure display output frames are refreshed only once per frame interval and thus only change content during the vertical blanking interval - so you don't get tearing mid way down the screen as you see portions of two source frames displayed in the same display frame.  The same is also true for GUI refreshes. 

Right, but if the TV is already at the same refresh rate as the video file, then the v-sync is useless.