The quad DAC is a legitimate upgrade to the G6's audio performance. The question is whether the G6 will represent the first time this capability expands beyond Korea.
The G6 was oddly fragmented between regions, with the US exclusively getting wireless charging at the expense of the quad DAC. LG isn't saying yet where the G6 will be available, however. Some models will include wireless charging, so it might be reasonable to assume that it should make it to the US.
For current G6 owners, LG has also announced a software update with features including facial unlocking, a low power consumption mode, and a warning if you inadvertently cover the camera lens with a finger - apparently something that can be an issue with the G6's wide-angle lens.
The G6 and the G6 software update will arrive sometime in July.