The Witcher 3's Bleak Cinematic Trailer

It's sort of difficult to understand why a game as good looking as The Witcher 3: Wild Hunt would rely on a CGI trailer, because it's simply doesn't need it. Do these things even sell games? I know I buy because of the way the game looks when it plays, but do people get excited by story shine? I mean, it's is really, really well done, but...

The Witcher 3 is due to land next year. We'll be seeing it at Gamescom next week...