The upcoming California presidential primary is going to be a great real-world source of insight on the perennial question:"What's wrong with paper ballots?"
Of course, paper ballots are a necessary component of elections in most parts of the US, but one variant of that question is about the so-called pure-paper election with hand-marked paper ballots that are counted manually. With this model in mind, people often ask why is voting technology needed at all?
As California will show, the most pragmatic answer is: because elections officials want voting technology instead of conducting pure paper elections. But why? Long story, but watch how things are shaping up in California, and the post election response, to learn why. A few months ago, the Secretary of State de-certified all but one of the voting machines that were in use in the state. More recently, only Orange County and San Mateo County (where I live and serve as an elections judge) are permitted in Februrary to use that one type of device. Everywhere else in the state, voters will be taking pens to paper ballots.
The next question is how to count the record numbers of paper ballots. In some cases, there may not enough of the old optical scanner machines (remaining as certified election systems) to go around, so hand counts will be done instead. Those who noted the mishegas in San Francisco's last election (see Thad Hall's commentary), just wait to see how the experience scales up at the state level.
Should be interesting!
One more thing - of course a non-trivial portion of voters choose paper ballots when the voting machines are available, but in doing so these voters give up several assurances about whether their votes count. More on that later.