Framerates beyond your display's refresh rate are not completely pointless, though a bit wasteful: they do mean that each frame as it is displayed shows a more up-to-date representation of the game state than if your framerate is matched to your refresh rate. In principle you don't need to render the excess frames: ideally your frame time is predictable enough you can kick off the render just before the display refresh, but the penalty is that if you miss the deadline you get some pretty jarring jankiness.