Hi.. (Paul)
The advantage for some (like me) is as follows.......
I have a large hardware synth collection. It is wired into a Focusrite Thunderbolt (24 inputs) array - that attached to DAW. However, unless I leave some synths unplugged, or route them through a mixer, I do not have enough inputs on the hardware. Depending on how you work that might not be an option - since you can record the audio of a part, then swap synths over. However, I have always liked the option to have everything playing in real time....
So... I have a spare audio interface. It would be useful to connect that to my Slave 2 and then plug some sythns into that. The audio / midi of those synths would then be controlled from the DAW in the normal way. In other words, the slave would be hosting VI instruments in the normal way, but could also deal with audio / midi coming through the audio interface into the slave....
I appreciate this is a long way from the intention of VE PRO...... but there you go :D
MArk