Of course size and scale matter. China can still oppress Hong Kong even with a secret ballot because Hong Kong isn't large enough even united. (or are they?). However most cases are at least covered by secret ballots.
>We don't just need votes to be anonymous and private (while still making the final result provable and public); we need votes to be so private that even the person who made the vote can't prove to anyone else what they voted for. [emphasis theirs]
This is the part I was saying doesn't seem so necessary.
I've contemplated that too, but I'm not sure it leads to better results. I think good results come from amassing voters who are genuinely engaged on an issue, and entrenching a means for them to become well-informed before casting their ballot.
A system to deliver that, blocks the noise of political issues I don't care about (I simply don't participate, which is a good outcome since my participation adds little-to-negative value) and surfaces those I do. It provides me with expert analysis, arguments and counterarguments (something like StackOverflow to bubble the best content to the top?). And it makes more economical and efficient use of my attention.