The way Virginia votes is a voter shows his/her driver's license, poll workers scan its bar code, check the living address (so you are at the right polling station), issues a paper ballot.
Voter goes to a booth, bubbles in the candidates, then goes across the room to the counting machine, feeds the ballot into the machine. The machine records that a ballot has been scanned (a digital ballot counter increases by 1). Finito.
I have no problem with a machine scanning my ballot (that would be the preferred way to count them anyway as long as the machine is available), but the accuracy of that account is only as good as the hardware and the software. And, as an experiment, in the last election, I deliberately did not vote for dog catcher. (I neither know nor care who the dog catcher is in Hooterville). The scanning machine did not flag up that I had not voted for dog catcher. It just recorded that a ballot had been counted. In a very close election up ballot, there may have been a scanning error on some of the ballots, but according to this law, it is not legal to count them by hand. I think that is improper.