Pastry fillings are like pie fillings on steroids! Yes, you can use pie fillings in your pastries and desserts in place of pastry fillings but they are not as good. Conversely, do not replace pie fillings with pastry fillings.
Pastry fillings are much more intense, concentrated, than pie fillings. In a pie, there is a lot of filling and not much pastry. In most pastries, there is a lot of pastry and relatively little filling. For balance, you need a more flavorful filling for pastries and a less concentrated one for pies.
When you choose your filling, consider the ratio of filling to pastry.
