The use of CGI, as it is currently being employed, misleads too many uninformed consumers. This creates an unrealistic expectation, which leads to disappointment from certain consumers.
I'm convinced that CGI trailers are used to get initial attention, regardless of how truly reflective they are of the gameplay of set game. This is primarily true for MMO's. Which CGI trailer for an MMO actually depicted the type of battle system within their game that turned out to be accurate? It's not even a case of graphics being close, everyone can agree that none of them are; it's an expensive attention grabber.
I think they have a place for creating a first impression for tone or story: see Dead Island 2 for that. It's just been more frustrating every year how less and less gameplay is being shown off (with the exception of Microsoft's E3, which had a surprisingly good amount of gameplay vs CGI).
