The most important feature of public elections is trust. Efficiency is one of the least important feature. When we moved away from paper voting with public oversight of counting to electronic voting we significantly deteriorated trust, we made it significantly easier for a hostile government to fake votes, all for marginal improvements in efficiency which don't actually matter. Moving to internet voting will further…
The US overwhelmingly uses paper voting (often paired with electronic tabulation). We can't "move back", it's where we are. Electronic tabulation introduces little risk when the ballots are paper.
And not all paper systems are good either. I'm sure everyone remembers the disaster that was the punch card system used by Florida in the 2000 election...