The NFL, like nearly all team sports, requires teams to both score points and prevent their opponents from scoring.
Scoring more points than your opponent is the basic (and only) formula to win a game, and it's how teams are ranked in the "AAP Ranking" system.
The AAP (all about points) Ratio is the ratio of points scored per game to points allowed per game. A ratio above 1.000 means a team has scored more points than it has allowed (and the reverse is true for a ratio under 1.000).
There are many statistics used in football. But regardless of the turnovers, yards gained, completion percentage or any other stat, the important thing is who wins the game.
And winning is all about points.