This recipe illustrated how the XRI Interaction Toolkit offers a simulated VR device that will map keyboard and mouse movements from our computer into right/left-hand controller actions. By importing the Mock HMD device assets and adding a prefab GameObject to our scene, we are able to run and test our VR project on our computer, without the need for an actual VR headset. This can be useful when no headset is available, or we are testing aspects of the project that don't need full user testing in an actual VR environment. In many cases, it will be much faster to just use this simulated device and run a scene in Unity than building an app and testing on a headset, or even using a Link cable/Wi-Fi and having to put on/take off a VR headset each time some aspect of a scene needs testing.
Of course, there will be many situations that can only be tested properly by running them on an actual VR device, but this Mock HMD device is a useful tool to have in any VR developer...