Avoiding tight coupling between the client & the business objects, increasing manageability.
Reducing fine-grained method invocations, leads to minimize method invocation calls over the network, providing coarse-grained access to clients.
Can have centralized security & transaction constraints.
Greater flexibility & ability to cope with changes.
Exposing only required & providing simpler interface to the clients, hiding the underlying complexity and inner details, interdependencies between business components.