Most of the games on Windows Mixed Reality via SteamVR function via some form of emulation, mimicking the peripherals of other platforms. For example, in DOOM VFR, recently released (and totally awesome), you can see HTC Vive motion controllers in the in-game menus, rather than Microsoft's own WMR controllers.

Sadly, this also means many games don't support WMR's joysticks natively either, meaning that in games like DOOM VFR, you have to physically turn, to well, turn. Physical movement in VR is not only disorienting for some, but for others, there simply isn't room to move around, unless you want to end up tangled in a HDMI and USB cable from your headset.