I think the idea is, at least in previous years, certain blocking animations trigger at certain thresholds with the straight pass/run block rankings. (last year it was 89 for run block). which does help the block. The power/finesse rankings are used to calculate matchup results. Defensively, those ratings are the amount of time it takes to complete the move, the blocking rating how effective the move will be/how well they block it. Realistically, who the hell knows.