You would see the following message when you first use BI Connector to connect from Tableau to Oracle BI (OBIEE).
This is just an informational message from Tableau and can be ignored. Check the "Do not show again for this data source" and carry on with your visualization.
The reason you are seeing this error is because BI Connector is a specialized connector that uses ODBC interface to specifically connect Tableau to Oracle BI's Presentation Layer. To keep it light weight and high performing, BI Connector implements only those essential functions that are of value for connecting to Oracle BI's Presentation Layer and does not use other functions that do not add any value. So, go ahead, check the "Do not show .." box to hide this message and create a stunning visualization!