"Technically" (lol) if the Steelers and Bills win out and KC loses out - bringing all three to 13-3 - there are still some possibilities due to the three-way tiebreaker where the Bills could be the #1 seed. However, let's be realistic here and say it comes down to whether or not they care about the second seed and having home field for the first two games (assuming they win the first one....)
...which brings us to this. Do they want the #2 seed? Benefit is they play at home - again if they win the first game - and are assured they don't have to play KC until an AFC Championship matchup.
However, that also means they might play a more difficult first round game oddly enough.
My guess is they don't want to travel to Cleveland or Pittsburgh (unlikely at this point) or Tennessee in the second round. Neither are conducive to the Bills' air attack and they haven't shown an ability to run the ball all game.
Unfortunately for the Dolphins, unless it's locked up after week 16, I think the Bills play to win in week 17.
I only say "unfortunately" because it makes the Dolphins chance a winning more difficult playing against not only starters, but game-planning. If the Bills don't need to win, not only will they rest some starters, but they'll play vanilla to keep down opponent game film.