Exactly. I was under the impression that G-sync only worked within a certain FPS range. Anywhere outside of that and it will not function. Which is the same as FreeSync.
The LG 34UM67 (2560x1080) and Samsung UE850 (4K) both have a minimum refresh rate of 40 Hz while the BenQ XL2730Z (2560x1440) has a minimum refresh rate of 30 Hz.
This may completely change the relevance of refresh rates when looking to buy a new monitor. Minimum refresh rate may become a more important number than maximum refresh rate, especially at higher resolutions.
Found that quote from another forum but I am unsure how true it is.