Wow that actually looks awful.
Pause @ 1:19 when he stands up and its like his hair is made out of cardboard with how it flows off the back.
Not to mention its flapping around while indoors more than Lara's in a blizzard:
https://youtu.be/wrhSVcZF-1I?t=42
Sorry but hairworks vs purehair, purehair looks much better and has less performance hit. See the above two videos
Like I said above, that video was taken shortly after launch. Those issues, especially with the hair physics were eventually patched out.
I do agree though that the particular hairstyle in that video looks awful on Geralt. The dramatically reduced hair physics is likely a concession that had to be made for performance reasons, since that haircut is free flowing.