Far from me to bash Shmessy. But from my simplistic perspective:
1. You put together a game plan that you think will bring you out on top with your available personnel vs. their available personnel.
2. You adjust the game plan during the game based on how things are playing out, and changes to available personnel (injuries).
3. You make end-of half/end-of-game adjustments to try and come out with the desired outcome, if the game is close.
In this case, BB chose to chew up some clock time and put it in the hands of his defense, and it worked (barely). There's lots of times he's taken a different approach with a game coming down to the wire.