Hand-kneading and machine-kneading pastry dough are two different ways to make dough. Each method gives you different results, and both have their own good and bad points.

Texture and Control
When you hand-knead the dough, you can control how it mixes better. You can feel the dough and check how thick it is. This way, you can avoid overworking it, which can make the dough tough. On the other hand, using a machine is faster and gives you more consistent results. But if you’re not careful, you might accidentally over-knead the dough.

Aeration and Temperature
Hand-kneading lets you add air to the dough slowly, which makes it lighter. This is really important for certain pastries like puff pastry, which need to have distinct layers. Machine-kneading can make the dough warm, which isn't great for delicate pastries. Too much heat can mess with the fat in the dough and make it less flaky.

Effort and Time
Hand-kneading takes more physical effort and time, but many bakers find it relaxing. Machine-kneading saves you time and is easier, especially when you’re making a lot of dough.

Learning Experience
When you hand-knead, you learn more about how dough behaves, making it a great skill for beginner bakers. In comparison, machine-kneading can help you speed things up once you have the basics down.

In the end, whether to choose hand-kneading or machine-kneading really depends on what you like, the texture you want, and the type of pastry you are making.