Except we have some studies that show they lead to and reinforce avoidant behavior, e.g. https://www.sciencedirect.com/science/article/abs/pii/S00221...

Some also showed no evidence of this, but avoidant behavior is pretty much universally considered to be a specific maladaptive behavior when it comes to treating PTSD in the long run. It has nothing to do with the idea that it is the same as exposure therapy.