God rested on the seventh day of creation. Why? He's ominpotent, right? So why would God need rest?
He doesn't. The point of that part of the story, and the reason many of our grandparents did not work on Sundays, is that no work is complete until it is appreciated. A crop is worthless until it is eaten. A symphony is worthless until it is heard. Work has no inherent value. Labor without reward is nothing more than good intentions.
Players need time and encouragement to reflect on their experiences and accomplishments. Cinematics, as they appear today, do not accomplish this. While they effectively pause gameplay, they also require rapt attention. The player is still working. Even a cinematic flashback of the player's own choices and experience is not good enough, if the player must remain actively attentive and cannot pause/review the sequence.
Players need downtime. By that, I mean players need time that is free of any demand on them, that lets them relax and lets the mind wander, reflecting and absorbing those memories at its own individual pace.
The developer's challenge is to encourage such downtime (even demand it) without disrupting the player's immersion in the game. Old films sometimes had intermissions accompanied by music and a static picture. The music helped keep the audience focused on the movie setting, but the removal of dialogue and visual action allowed people to reflect (yes, I know that wasn't the primary purpose of those intermissions). Likewise, game intermissions keep the player focused on the game setting, but offer respite from interaction.
One of the things the original Everquest game did right (though, perhaps, too severely) was to force rest. Resting not only encouraged chatting between players, it also encouraged reflection on each and every experience. Honestly, I complained about it at the time I played EQ. Being used to console games, I disliked the forced pauses. But it grew on me, as it did on thousands. Notice that the resting EQ character (and so, also, the player) remains surrounded by the moving gameworld during rest.
I'm constantly talking about dynamics, and there's one more use for them: scenery. To simply absorb and enjoy one's surroundings is something we all experience at times. Smartly placed and presented, it's a pleasure that makes downtime not difficult to bear.
I'm posting this a little early because I won't have internet access tomorrow.