Hi Mandar,
Please check advantages of MSP:
Widely Used tool for project management
Easy Integration with other Microsoft Products
Desktop application
integration with SAP PS using Open PS
Integration:
Open PS is used for integration with SAP:
Open Project System - Interfaces to the Project System - SAP Library
check SAP Note-505734 for OpenPS
also check Microsoft Project Server 2010 Integration with SAP which is released by Microsoft
major use of MSP is to schedule and planning.
Thanks
Sunil