You ain't kidding. This is HUGE!
Yeah, to get G-Sync into more hands is awesome!
Killing off input lag & graphical tearing is a VERY big deal.
Coupling G-Sync with monitors with higher refresh rates (i.e. above 60fps - think say 90hz, 120hz, 144hz, 240hz, etc) is going to be ideal - as you can kill the above stuff and also minimize any feeling of lag from any crazy framerate drops (like losing 30 frames or so).
I love my G-Sync 1080p monitor on my desktop (240hz refresh rate) and my SC15 laptop's G-Sync supported screen (120hz).
Though, these monitors that I have are before G-Sync going more "open" - so those do have a special controller/CPU Nvidia put on them to control the framerate, kill input lag, and kill graphical tearing. So I am also guessing those, w/ FreeSync that are going to use G-Sync, those FreeSync monitors don't come w/ those controller modules/CPU's on them. Those might possibly need to buy a better card (i.e. say a 1070, 1080, 2060, 2070, 2080) and/or a better CPU (higher end i5's or i7's) to get the most out of this.
We won't know 'til next week, when benchmarks likely will pop out.