The privacy of voting booth could give at least some chance to change mind/lie to the third party.
In fact, with a blockchain-based system, the vote could be held in "limbo" until the voter decides to cast it, or you could give the option of creating fake screenshots to deter anyone "buying votes". You can't do this with a paper ballot.
The real problem is compiler and hardware level.
And the president is - right now - conducting a denial of service attack on it.
If that doesn't show that remote voting is vulnerable I don't know what does...
> And the president is - right now - conducting a denial of service attack on it.
Or at least miming one, perhaps to provide political cover for Republican-governed swing state legislatures, seeing the problems of in-person voting in the pandemic and armed with the telegraphed disruption of vote by mail as cover and polling data as motivation, to simply exercise their prerogative to cancel public voting and assign a set of Presidential electors without it, which the Republican control of the Senate can guarantee withstand any challenge in the electoral vote count.
If he really wanted electoral chaos by disrupting vote-by-mail, there'd by no reason to telegraph it; the reason to telegraph it is because he desires a response that it either provokes or justifies, as much, more than, or perhaps even instead of the disruption itself.
This is insufficient. In-person paper voting allows the voter to toss out their marked ballot and get a fresh one. You can take a photo of your ballot, but it's hard to prove that's what you actually casted. Poll workers will tell you to put your camera away near the ballot box, to protect other voters' privacy as they submit their completed ballots.
When you vote right now, your vote is (theoretically) tied to your identity, because every ballot has an id tied to it, so it's not like you'd be giving up any more anonymity than you had. I don't know of any practical fully anonymous election systems that are post-hoc verifiable, but maybe somebody does.