For teams that have multiple bowlers of similar quality it makes a lot of sense. Any players with injury history (Richo, Mills, Dorf), it makes sense for rotation.
For teams like thunder, where they have two different international bowlers and then 3 paceman that offer different strengths (sandhu, McAndrew, Doggett) it makes sense they are rotated based on the pitch and whether Farooqi/Qadir play. I don’t think their rotation will have anything to do with fatigue but pitch conditions. Strikers potentially in this situation too.