The VR goggles plug into one USB port, the sensor (that watches the goggles for head movement) plugs into a second USB port and there is also a sensor plugged into a 3rd USB that allows the remote controller to talk to the computer. The googles need the horsepower of the PC to send the images to the goggles at a fast enough rate to avoid stuttering. Think of it as strapping two pc monitors to your head, you still need the pc to send the graphics to the monitors.
And if you think AFFS2 is good on a monitor you would be in utter disbelief if you tried it in VR.
One of my favorite things is to take someone who has never experienced VR, sit them in my sim seat, strap the Rift goggles on them, load up AFFS2 and stick them in a Hornet or Eagle over the Grand Canyon... the inevitable ear to ear grin is priceless.