Am I kind of right ?
"Ko" is effectively one of those situations where you can hope to get two moves in a row (e.g. if your opponent spends his next move filling, or otherwise removing the ko).
On the other hand, if your opponent chooses to allow you this, it means that the value of the ko is large. (Otherwise he would answer your ko threat and ignore the ko).
Balancing the value of a two move "ko threat" against a ko itself, adds dimension to the game. So does the art of creating these kos, that allow you to make these threats.
I would say the added dimension comes from the "long-range" nature of kos. It is possible, through a ko, for two, otherwise loosely linked regions to be directly compared. Each ko evaluates the entire board in the context of the local position.
In that sense, it creates considerable added complexity to a game.