There is another reason as well.
Saves at the end of the turn is a good game mechanic because it is easy to remember. You are dazed? It's the end of your turn? Take your save.
Durations that end at the start of the attacker's turn, the end of the attacker's turn, the start of the target's turn, or the end of the target's turn are inferior game mechanincs that require that the DM and players keep track of:
a) Which of the 4 types it is.
b) And in two of the cases, which attacker is relevant to when the duration expires.
The way we handle this in our game is that the attacker keeps track of this for 2 of the cases and the target keeps track of this for 2 of the cases. However, we still have occassions where a player will forget that an effect wore off at the end of his turn for example. So, the NPC miniature still has a blinded token or a dazed token or whatever on it, even though it is not supposed to still have that condition.
