The video gets a lot of stuff wrong.
First the S-72 was not an X-Wing. It was the Rotor Systems Research Aircraft (RSRA), whose purpose was to test various rotors. Here's a picture of the S-72 with an X-Wing mounted, you'll see it's much differnt from what's in the video.
Second, those wings are there to provide a fallback in case there were issues with whatever rotor was being tested. The goal of X-wing was that the rotor would be stopped in flight and itself act as a conventional wing.
Third, the X-wing
never flew on the RSRA (note that isn't an X-wing rotor in the flying shots) . An earlier version did make a takeoff on a highly modified Kaman Seasprite, but it just lifted into a tethered hover and made no attempt to attempt any horizontal motion, because the flight control system couldn't handle that.
That last factor is why X-Wing never went anywhere. The required flight control system and supplying the varying bleed air to the rotor would have been hideously complex and the craft would require a lot of power, especially during transition (It was speculated that an X-wing would not be able to start/stop the rotor for transition and maintain level flight). It would be very expensive but wouldn't offer much advantage over, say, Tilt-Rotor. It might dash maybe a hundred knots faster, but its cruise would actually be lower. While the V-22 doesn't have the world's greatest autorotation characteristics (due to a unique USMC requirement for deck spacing, other tilt-rotors are better) it beat the heck out of X-wing which would have the characteristics of a brick.
It was an interesting concept that just didn't pan out.
