Bottom line: Blockchain can help a bit with voting, but it’s not doing the most important part of the work. It doesn’t help tally secret ballots in a publicly verifiable way. It doesn’t provide individual verifiability that a ballot was correctly encoded. And it’s not useful for voting eligibility, since that’s all about human authentication and a centrally produced voter list. At best, in voting, Blockchain can be a ledger that helps us track the voting metadata.

Then there’s the need to check voter eligibility, a critical piece of global verifiability. No matter what technology we use, we need a clear list of eligible voters, and each voter should get to vote only once. Ultimately, the list of eligible voters is set in a centralized way: it’s produced by the State. There’s nothing distributed about voter eligibility. Even when there is federation / delegation to individual counties, like in the US, there is a centralized effort to cross-check that a voter isn’t registered in multiple counties.

In a typical election setting with secret ballots, we need: enforced secrecy: a way for each voter to cast a ballot secretly and no way to prove how they voted (lest they be unduly influenced) individual verifiability: a way for each voter to gain confidence that their own vote was correctly recorded and counted. global verifiability: a way for everyone to gain confidence that all votes were correctly counted and that only eligible voters cast a ballot.