It immediately raised a suspicion, could the government use "updating a vote" to change the vote of the voter after they voted. There were suspicious bursts of votes for government candidates during early morning (3:00-12:00 AM) between 2nd and 3rd voting days. Could it be re-votings? Who knows, public blockchain has no way to find this out.
How can an observer distinguish between a real voter voting the second time, and the government voting second time in his name?
Furthermore, to cancel the previous vote, you need some way to link the new and old ballots. In the case above, there was a non-public database (a blockchain), unavailable to observers, which kept the needed information. And theoretically it could allow de-anonymize the voters.
So what I wanted to say that electronic voting is a garbage only convenient for fraudsters.
[1] https://github.com/moscow-technologies/blockchain-voting_202...