Interesting stuff, so it works a bit similar to Bromium if I'm correct. I wonder if third party apps like AV's and sandboxes will eventually be able to make use of Application Guard. Here is some more info: https://blogs.windows.com/msedgedev/2016/09/27/application-guard-microsoft-edge/
Only applies to Win 10 Enterprise as noted in the link Rasheed187 posted: Windows Defender Application Guard for Windows 10 Enterprise. Application Guard provides unprecedented protection against targeted threats using Microsoft’s Hyper-V virtualization technology.
The question is also how user friendly hardware based sandboxes are compared to software based sandboxes. Of course it's more secure, but what about if you need to save data?
