They do in some counties. I'm a pollworker in Alameda County and every precinct uses an optical scanner (made by Sequoia). At the end of the night the memory pack is removed and taken back to a return center to be counted. The paper ballots are boxed and sealed in case there are any problems with the electronic tally.

Speed-wise, it only takes the machine about 1 second per ballot card.

Just to be clear, you are arguing that that scantron machines are expensive and not feasible at every polling location so instead we should provide dozens of more expensive electronic voting machines at each polling location?