What is the difference between using QPluginLoader and QQmlApplicationEngine::importPlugin?

[VRHans]

If I manually load the plugin with QPluginLoader and ask the extension to register its types, is that the equivalent of just having the Qml application engine import it itself?

I ask because I'm going to be instantiating components from these plugins dynamically in my UI and I need to pass information back and forth between my hosting application and the plugins. Do I need to use both? Or is ::importPlugin just a helpful wrapper of QPluginLoader functionality?

Thanks :)