Apart from the reasons you mentioned, the advantage of byo-yomi or Fisher time over the "add time after move 40" as often used in Chess, is that it doesn't crea

Apart from the reasons you mentioned, the advantage of byo-yomi or Fisher time over the "add time after move 40" as often used in Chess, is that it doesn't create an artificial barrier. What's so special about move 40? If you analyze chess games, you'll probably find that moves 40-45 are on average more accurate than moves 35-39 even it feels this number shouldn't be part of the game.