The Americans usually respond to this with "that doesn't work in the US, because it's too big, and you would need too many people to count the votes." Apparently it's not so obvious that in a bigger country you also have more people available for counting.
Paper voting is still done in many, many, many places in the US. It's still a substantial fraction of US voting.
It is true that counting paper ballots in the US is a more time-consuming process than elsewhere, because it's perfectly normal to vote for thirty different elected offices in the US and say, five referendums.
