I will test a flash's performance when many user use it at the same time. As we know much departments are loaded to client browser, others still be server side. We want to know whether the flash is display well in this case.
Flash is an (OSI) application layer instrument which runs on the GUI. If you need to test the actual execution of flash, then you need to use QTPro or WinRunner. Otherwise LoadRunner will download flash content just fine from the server.