The V3 will accept a line-level signal. Even with minimal gain, the V3 gain stage will impart a sonic signature to the recording (as will any gear in the chain). Without knowing who did it and why, my guess: they ran V3 analog > 722 for the same reason people run that set up in the field with mics, i.e. they prefer the sonic characteristics of the V3 gain stage and the ADC of the 722.