In the (upcoming) scenario of running tests against any RCP application (Eclipse IDE, JBDS, whatever RCP...), surefire is able to compute the value of product and application for the given RCP,
So let's say we want to test it against JBDS, overriding the product makes that even if the RCP is JBDS, it will test org.eclipse.platform.ide, which can be different on some points.