They're "statistical" in that they're a numerical result of a formula. But they have nothing to do with points spreads.
Think of the entire group of teams from top (Covington Catholic, 137.3 rating) to bottom (Jenkins, 1.0). CovCath wouldn't be a 136.3-point favorite over Jenkins.
CovCath is simply 136.3 points ahead in the rating number.
I guess the number really has no actual "value" other than to give an indication of whether the team went up or down from week to week and who would be "favored" in a given matchup.