Yes, definitely worth it. For old games it's redundant, but if you're running new games at 1440p and above then it'll allow you to run the games at higher settings without having to worry about not looking smooth when fps drops.
One caveat to a GSync monitor, however, is it turns off when FPS reaches above the monitor's refresh rate. This is fine if the FPS stays above your monitor's refresh rate consistently, however if it drops below it takes a moment for GSync to initialise again so it can cause a stutter (I don't often notice it though).
The solution to this it to set the FPS of the game to 1 frame below the monitor's max (for instance, I run my monitor at 90hz, so if I can I will set the game's max FPS to 89 or similar).