>>72382310
Variable refresh rate makes bad frame pacing impossible. With a fixed refresh rate, if a frame takes longer than one refresh, it will be displayed for multiple refreshes, while the next might be displayed for only one refresh. You can have one frame displayed for 33.3 ms and the next for 16.7, creating visible stuttering. With variable refresh rate, if a frame takes longer than the last to be rendered, it will simply be displayed longer, by making the time of the next refresh longer, so frametimes won't vary as wildly as with a fixed refresh.
With variable refresh rate, you can let your framerate drop below your refresh rate without getting all the stuttering that entails with a fixed refresh rate, as your framerate effectively dictates your refresh rate within a certain window, making drops less perceptible and bothersome.