Multitrack recording. You have 3 pair of analogue outs, 3 pair of USB outs. That's SIX stereo channels at once. That's twice than most synths do. I honestly can't think of this as a "flaw", and you probably should have read the manual/forums/whatever before buying
If the Virus had a USB3.0 interface it probably would handle some more digital channels (like 8/10 digital stereo outputs + 3 analogue stereo outputs), but the USB1.1 specs for bandwidth don't allow this. You should know such things before buying expensive gear.