But I what is written over and over is more on the lines of "I don't trust the process". I cannot blame anyone for not trusting Internet voting: I am a professional SWE, and it would be impossible for me to establish that any such system isn't pwned. Too much code to audit, hardware that's impossible to audit. But it's pretty trivial to demonstrate to the layperson how paper voting works, and how poll observers can prevent that process from being subverted.
However, those are in the context of whatever political system they're in. No level of efficient election design is going to put a dent in the fact that California loves direct-elected downballot offices (e.g., treasurer, controller, insurance commissioner, state judges, local judges, etc.) and referenda, which all result in super long and complicated ballots with 50+ questions each.
You get text messages each step of the process too. “Your ballot has been mailed”/“your ballot has been delivered”/“your ballot has been received”/“your ballot has been counted - thanks for voting”.