That's how all plugins that generate midi work, you send the midi output to a vsti when you are happy with the midi track or phrase you drag it into the DAW.
Same with Audio, you may have Direct Input multiriffs in one instance of the Plugin, you load Amplitube/Guitar Rig after the BiabVst or create an audio send to a track with Amplitube/Guitar Rig on and simply solo (well that's not a simple action how it is now) the riff to preview in situ.
That's why other Plugins have solo/mute buttons, so you can see now why solo mute are totally important (and the track midi channel setting), you need it to be professional like the session musicians that play the tracks.
The BiabVst originally worked the same as the video below, no syncing just drag tracks out, no advantage than using Biab in Plugin Mode.
If you just want to drag all the audio and midi tracks into the DAW just use this method: