Until this rule change, the Football League used Goal Average (goals scored / goals conceded) to decide final positions when points were level. Changing to Goal Difference first and foremost, followed by goals scored was not universally popular with many old hands noting quite correctly that goal average was less likely to have two or more teams finishing with identical records.
Arsenal benefitted from goal average to become Champions. They would benefit 23 years later as the win at Anfield gave them the League title on goals scored. Had goal average been in existence, the 2 - 0 victory would have been heroic failure with Liverpool taking the title. Arsenal would have needed to win 5 - 0 under those rules.