Configure a single OLAP connection to SAP BW, so we can create many BO documents based on single OLAP Connections which will get data from any cube or query resides in the SAP System.
If we have separate queries on many different cubes in the BW server, we can gain access on all the cubes and queries with the single OLAP connections.
which is also easy to maintain , otherwise we have to give access on multiple OLAP connections which were created to access individual cubes to refresh the reports in BO.
PF the below screenshot and best practices document