Possession is an extremely common topic in soccer discussion. It's almost a written arrangement: The best (and richest) teams in Europe -- think Manchester City, for one -- will dominate the ball and take it back the moment they lose it, while the lesser (and/or less monied) teams will have to make do without it.
In this, the age of Pep Guardiola, having the ball is tantamount to winning. If you know who had more of the ball over the course of a given season, you probably know who ended up with more of the points.
Points per game for teams with different possession rates in Europe's Big 5 leagues (2017-18 to present):
Over 65% possession: 2.