...
The report will take a connection from the Jira database connection pool (the same connections that are used by the Jira application internally)
Of course, you can use the database vendor's JDBC instead. This approach has some drawbacks and advantages compared to our JDBC driver. The advantage is that the database administrator can provide a database user with limited access to the data model (read-only and with reading privileges for some tables only, for instance). The drawback would be that it might require to include the users' credentials (username & password) in the BIRT report to access to Jira database connection. You have to evaluate the pros and cons and make the right decision for your organization.