Reduce the ko
In a ko fight, when the ko is a direct ko for one player (A) but an approach ko for the other (B), player A can use the time B spends on approach moves to reduce the ko, i.e. reduce the loss resulting from losing the ko. Although this way the ko becomes a direct ko for both, it also becomes heavier for player B. Player A will likely gain a bigger compensation.
An example of this can be found in Ko fight example from a pro game - 1