Someone obviously made a slip up and mistook "VESA Standard Adaptive-Sync technology" to Nvidia's G-Sync technology, but if was funny to see Nvidia to list competing technology at its G-Sync Geforce website. .

The latest list of G-Sync monitor has ten monitors supporting this technology, and G-Sync enabled monitors usually cost a few dollars more than those without sync technology. Still, if you are a serious gamer and you use Nvidia GPUs, you kind of need to get G-Sync as it will improve your gaming experience.

On the other hand, AMD has fifteen FreeSync monitors listed at its official site with an exception - not all of them are available and shipping. Some of them are available now, a few are available for pre-order, but in any case the list has a total of fifteen FreeSync or "VESA Standard Adaptive-Sync technology" monitors.  

Both lists have the BenQ XL2730Z Gaming Monitor listed and, according to the BenQ website, this monitor clearly supports FreeSync. FreeSync is sometimes advertised as "VESA Standard Adaptive-Sync technology" as this is part of VESA standard. Maybe someone at Nvidia jumped the gun, telling us that a similar specification monitor with G-Sync is on the way? Nvidia does have a 24-inch Benq 144Hz gaming monitor with G-Sync.

Just in case that this gets changed, we have a screenshot below.