> This on-chain voter ID would never have to be "mapped" directly to a voter

The government will generate these IDs and then mail them to people. Who’s stopping them from recording the mappings?

What's stopping them from not properly separating the outer and inner envelopes in mail-in voting? Or correlating poll booth entries with checkins? Nothing. The system fundamentally assumes the organization operating the poll is trustworthy.

In case you are interested, the thing preventing those types of shenanigans from happening is volunteer observers from various parties. The inperson and physical nature of things makes it much more difficult to break.

Yes, and volunteer observers could also ensure that the keypairs mailed out to people are never revealed.

1. An airgapped computer running a keypair generation program generates millions of keypairs.

2. This prints these millions of secure keypairs with the keypair facing "downward".

3. In a publicized setting with volunteer observers, the private keys are sealed into envelopes which don't yet have names or addresses on them, and secured with tamper-proof seals.

4. These ballots are sent through another printing system, which adds an address and name to each ballot, at random.

5. The ballots are mailed out.

How is that any different?

The level of complexity for auditing here is much, much higher than the paper system. How do you verify that the software wasn't backdoored? How do you verify that the computer actually ran that software? What if the hardware had a backdoor? What about the compiler? Even the printers could be compromised.

Normally, I would consider these types of issues simply paranoia, but in this case we are talking about very high stake elections that control the spending of trillions of dollars.

The big risk of UBI is that it can lead to a rise in populism. This is very obvious in the former communist countries of Eastern Europe. A large part of the population is fully dependent on the state for pensions or some sort of basic income and lots are even working as civil servants. This sizeable section of the population is very susceptible to populist promises or scares. “If X wins, they will cut your pension” type of rhetoric. This has very perverse and non-intuitive consequences. People vote for obviously corrupt leaders in the hope that they would share the spoils with them, and to some extent they do. If a western country adopts UBI, I can easily see a similar path. Maybe not immediately but over 20-30 years as more and more people become dependent and know nothing else. This is a very slippery slope.