Is "virtual" a pun? haha (good one if it is)
I guess stacking is audible with microphones for the noise, but a poor adc is either heard outright (ie fast track ultra vs clarett) or heard from multiple conversions (i.e. bussing through hardware or reamping)
It's been long debunked by Ethan Winer almost a decade ago, as has the multiple conversions myth..