I think in your thesis you make some interesting points on how E-Voting systems differ. But I have critizism. Let me paraphrase your points:
1. Paper ballots are in some ways more ambigous, because there are many ways to scribble a sign into a circle, a fraction of which will not result in the intended outcome
2. Understanding these handwritten symbols is harder than understanding the electronic system, because of that ambiguity
3. People understand the paper ballot system, but there are some statistical checks and security measures that they don't understand or know of, so their knowledge of the paper system is superficial
4. Trust in voting systems does not primarily arise from understandability but from trust in other people. To quote: your grandmum doesn’t have to become an expert cryptographer in order to trust a system like X. She just has to believe that cryptography experts exist and at least one of them would speak out if this transparent voting system was not as secure as the election officials claim
I don't want to question your thesis here, but I teach electronics and programming at a University level and points 1 and 2 are ridiculous and maybe even disingenuous. Sure, I understand that for a certain type of mind a digital/electronic system feels less ambigous and more clear. But most people are not like that – not even among academics – not even among academics that involve themselves with technology.
Point 3 is a rethorical trick that – if applied equally to E-Voting would be a strong argument against it. Yeah sure people don't understand X completely so lets do Y which is one-thousand magnitudes more complex is not an argument in favour of Y even if phrased in such a way.
Point 4 is the actual thought we disagree about, but given the unscientific nature of the 3 arguments before I can't simply trust you that you did research here (there are no sources cited that strengthen your point either). So as it is you just stated the opinion, as I stated the opposite. Sure, paper ballot elections are not dead simple, but any living being with basic understanding of object permanence could veryify a ballot isn't manipulated by just standing next to it. Meanwhile with computers you have to delegate that trust. And as computers can be reprogrammed, potentially remotely, even your experts can't be sure – especially in elections where powerful nation state actors seek to destroy the public trust in your election. This is a problem – just claiming that it isn't doesn't cut it. And people who claim that it isn't should not be the ones designing such systems.
The important thing to understand about agreeable consent is that a person's willingness to subject themselves to the will of a democratically elected majority is directly linked to their trust into the process. Your voting system has to produce that trust even if voters don't want to trust the process. The surest way to do that is to get a part of them involved into the process – ideally not always the same people. If then a single poll watcher claims a thing and 400 others that have been present plus three trusted NGOs can claim otherwise the election is not in question. Someone will have to convince me this works for E-Voting with a bit more than rethorical tricks.
Note that I am not against E-Voting per se. I just don't think the highest stake elections which have the potential to shift political powers should be electronic/computerized.