Paper systems are pretty hack resistant. Duplicating ballot papers requires large printing presses and a system for distributing the ballots. If it was a proble

Paper systems are pretty hack resistant. Duplicating ballot papers requires large printing presses and a system for distributing the ballots. If it was a problem then standard secure printing techniques could be used. Vote tallies from the polling booths can't be faked, so ballot boxes would have to be stuffed in real time. Stealing votes is also difficult and has low marginal gain in close elections. Ballot collection and retention scales great. We have trucks and warehouses as part of the regular economy. The cryptographic properties you mention seem nice, but no-one has implemented them. Paper is also great for anonymity, cost and consistency.