With paper ballots around the world there are already attacks at scale. Take the latest national election in the USA. Republicans claim that Democrats shipped in fake mail-in ballots or harvested them from old people, and said “trust us”. Democrats claim that Republicans closed polling stations and disenfranchised many voters at scale in districts that historically voted Democratic.
Witness all the rigged elections around the world, some strongmen getting 99% of the vote at scale. What good are the paper ballots in, say, Belarus if Lukashenko says he won? Is an average person going to be able to somehow know what happened in their own pollung station after they left, let alone across the entire country?
Having mutually distrusting parties have access to each other’s work is the very thing that enforces byzantine consensus but it can be checked and verified on-chain as each party signs off on the result, so anyone can check that 1) they looked at it and 2) they were satisfied. That’s far far better than hearing someone say “it went fine” about paper ballot recounts.
Furthermore, everyone being able to make sure their vote was counted by eg checking Merkle Proof is far more secure.
None of the above failure modes would be an issue if everyone who wanted to, could vote from their computer, scanned the QR code with their phone to verify their choice, and signed with their private cryptographic keys derived from their IDs.