A 49ers loss allows the Saints to "essentially" control their own destiny for the playoffs
Well of course it is.
Assume ...
Cardinals or Rams claim Wild-Card # 1 .
Saints win out.
Saints : 10 - 7 -> Wild-Card # 2 or 3
Niners : 10 - 7 -> Wild-Card # 2 or 3
Eagles : 9 - 8 -> Miss playoffs by losing 1 game.
If the Niners are the team that loses at least one game and the Eagles win out, then the Niners finish 9 - 8 and miss the playoffs.
If Cardinals, Niners, Eagles and Saints all finish 10 - 7, the Cardinals miss the playoffs based on having the worst conference record.