PI to BI

Hi Gurus,

Our client have PI (formerly XI) and have multiple source systems. Client is pushing data from PI to ECC. Now my task is to extract the data in BI system and the source is non SAP (RDBMS). I know that I can use DB connect to extract the data but client says as they have PI why cant we use it.

How should i convince my client that DB connect is the right way to go??

Thanks

Sri