First off Mass Effect's sex scenes are arguably some of the worst because they are meant to be taken seriously but just end up being dropped on the player's head because Bioware hasn't figured out how to do relationship progression correctly yet. Secondly the scenes in God of War have never added anything to the games and could be safely ignored, they have never been intended to be serious. If you think that they are trying to market the game with this scene you are an idiot.