I mean... will Gsync act just like Vsync once reached the refresh cap or will it allow to avoid tearing, locking the max amount of fps generated by the GPU to 60 and syncing the frames perfectly?
If you've been a good boy and watched all of TTL's videos then set some time aside to give these a watch, you will catch on much faster than trying to explain post by post. To simply answer your question G-Sync will behave like Adaptive-Sync except the monitor refresh rate will follow the card up until the point where it can't then it behaves like V-Sync. Tearing should never become an issue and frame lag should always be less than or equal to that of V-Sync.
It's of most distinct advantage when your GPU setup can't keep up with the monitor hence why it's only typically found on high-spec monitors. If your graphics setup can smash out 4k at 60fps then it doesn't really help but being realistic I don't think we've reached that point in GPU's yet.
https://www.youtube.com/watch?v=KhLYYYvFp9A
https://www.youtube.com/watch?v=Z_FzXxGVNi4
JR