Reason moving up props boxers up is because it is hard to do size makes a difference. Holyfeild being undefeated at cw would mean nothing compared to moving up being a hw champ again and again. Micheal Spinks winning HW title put him higher then winning another lhw even though it was deep. Leonard, Duran and Hearns winning titles way above there starting weights helped define greatness. People always talk about pound for pound who would win if they were same size the people who move up and beat them put it to rest shows they can makes them greater to a lot of people.