When it comes to the association between films and video games, it's one I think can become a mutually beneficial relationship, but only when the participants in these two different mediums have mutual respect, and don't turn it into some kind of dom/sub relationship akin to 50 Shades of Grey. Overall the prevailing attitude among film producers seems to be looking down at video games like some bastard child they're embarassed to acknowledge no matter how talented they are. The producers, writers and directors seem to have little to no respect for the audiences that enjoy video games because they tend to keep to the attitude that there's nothing thought provoking in what they continue to see merely as an electronic kiddie toy. Among Hollywood actors, there seems to be somewhat more respect for the medium, at least with newer generation actors, most likely because over time some of them have actually helped work on video games, providing voice acting talent, and so they've gotten exposed to the actual thought and craft put into writing plots and stories for games.
Meanwhile, on the game devleopers' side, as Yahtzee said, they seem to put a lot of stock in getting their franchise or individual game made into a film. My reasoning, and I think Yahzee himself may've been pointing to this too, is that reason so much stock is put into having your creation made into a film can be summed up in one word: validation. To some game makers, it seems as though the game-to-film treatment is the only way possible to get the world at large to recognize them as a "real artist." Although sometimes I suspect there may be some haughty attitudes on the game developer's sides as well, since often games made as tie-ins to films show a distinct lack of effort that mirrors the lack of quality in game-to-film adaptations. However, nowhere on the film industry side does there seem to be a mirror for the more submissive attitudes sometimes seen among game developers toward film companies.
Thankfully this doesn't seem be an across-the-board attitude, as some game developers like Hideo Kojima have shown they have more self-respect for their work. In fact, the not-too-long-ago cancellation of "Silent Hills" takes on a new level of tragedy when you consider it was being co-developed by both Mr. Kojima and Guillermo del Toro. It was a sign of mutual respect; a renouned film director working together with a renouned game designer. Thankfully there were reports after the cancellation that the two would be working together on a different project, so there's still hope, but for the corporate heads to have killed this project was a terrible decision (as Jim Sterling likes to say, "Fuck Konami!"), both for the franchise and for the game industry. Silent Hills could have been a bridge between the film and game industries that showed when the creative minds of the two industries regard each other as equals and cooperate on those terms, they can produce something great.
Now, personally I'm not down on films as a medium. While games do provide interactivity to open up all sorts of ways to reach an audience, sometimes a passive role is needed in order to ensure the desire message is brought across. The gravity of a scene could be lost if during dialogue between characters you could make the player-character jump on the NPC's head and do an Irish jig. Also if one maintains constant control of one's character, it can be possible to miss critical moments by looking in the wrong direction. Game developers can try to avoid this by drawing attention to setpiece moments, but no guarantees can be made unless control is taken away from the player momentarily to ensure they're not going to miss something critical. That's partly why I don't mind cutscenes; they ensure key plots developments don't get lost. They also allow a player-character who has a voice, face and personality of their own to be seen and to act as they naturally would (as opposed to the teabagging douche they may act like, depending on who's controlling them). If it's in service to the plot and is well done, I don't have any objections to cutscenes. Conveying a desired message is worth a moment of non-interactivity, in my opinion, as long as opportunities to take advantage of a game's interactive nature aren't squandered in the rest of the game.