Well, I'll grant you that there may be infinitesimal differences from digital print to digital print of the same file, but those differences (absent a mechanical malfunction) are not meaningful in any relevant sense.

The printer (the person, not the machine) does not press "Print" and then say "Ooohhh...I hope this turns out to be a good one!" Instead, he enters the quantity (50, lets say), presses "Print" and expects 50 identical copies.