NVIDIA GameWorks Integration

Serious Question: What exactly is the purpose of having HBAO+ and VXGI in a single build? Based on what I know of the technologies, VXGI has AO, and according to the slides that posted earlier, it’s more costly than HBAO+, but MUCH higher quality, and still runs on low end well. I understand that there is a gap between SSAO and VXGIAO, but is that gap really big enough to be worth supporting HBAO+ alongside the other solutions? I’m just not sure if it fits.