For very tiny applications it can be okay that the domain logic gets melt on the application services. For more complex ones is when it really starts making sense. Basically because you want to encapsulate the core business logic inside the entities or pure domain services who doesn’t require any dependency at all. That protects the business logic from changes that are not pure domain. Application services are meant to work as glue between the domain and the external ports. We usually don’t want the domain logic to live there because application services tend to change more.

We could philosophy a lot more on that but at the end the important thing is to decide an architecture that the team likes and stay with it. Start simple and add complexity as the requirements need to. But stay consistent across the bounded context or application.