Frozen puff pastry is considered an acceptable shortcut even among some pro pastry chefs. The key is looking for a product labeled "all-butter."
Some store-bought puff pastry brands use vegetable oil rather than butter, creating a less satisfying taste and texture.
All-butter frozen puff pastry tastes richer and more like homemade. Pastry made with vegetable oil may be flat, underwhelming, and less pleasant overall.
Butter is a leavening agent, releasing water content and creating steam. This steam creates pockets of air as the sheets of dough are pushed apart, creating light, flaky layers.