Just because a team has to win for the playoffs doesn't mean they will and the oddsmakers know that too.
SF had 4 turnovers last week and that was their downfall. This is their Super Bowl to knock off a divisional opponent here on National TV Saturday. TE George Kittle is back and will give a boost to the SF offense.

Also, the NFL Saturday visiting teams have covered 68% the past 5 years and already 2-0 this year so we have that on our side as well.