The way it works is simple: The game auto records (or you can start recording) every 15 or so minutes of gametime into memory. Then you can replay those 15 minutes to watch yourself in your adventure while having a cuppa.
It would be great to zoom about and watch yourself enter a dungeon, creeping forward towards an unsuspecting monster, but knowing that you never saw the extra two Death lords nearby. Remembering the shock as your character is suddenly assailed by more enemies than he expected, fleeing but at the last minute, his Follower dives in and takes the pressure off the Player and the Player returns to fight to help slay them.
Or maybe watching a huge panoramic type view of Dragon versus player battle with guards involved and how you just managed to avoid being flattened by its tail.
Then you could save the Replay for future viewing or even story telling.
