As per tutorial, SAP PI/PO is not recommended in enterprise SOA in following cases:
- SAP PI is not recommended for synchronous communication as it will put a significant load on the infrastructure service for servicing asynchronous request
- SAP PI is not recommended for UI driven scenarios if the backend is exposed as enterprise services
- SAP PI is not needed for intermediation if a non-SAP backend like J2EE or .NET platform is exposing business services in a UI scenario