The concern isn't only coercion, it's also vote buying (which was very common at least in the UK before the secret ballot). If you can take the money and then vote for someone else, retail vote purchase falls apart.
The existence of postal voting has already cracked this one open a bit, though.
Re:In Praise of Chris Krebs
by benmmurphy on Saturday November 21, 2020 @02:47PM
(#25172263)
Large scale use of absentee ballots or mail in ballots also allows coercion of voters. Most of the E2E systems are designed so it's not possible for a voter to prove to a third party who they voted for.
I think the current election, or even just how screwed up elections are in other countries, show that it's probably an order of magnitude more important to have faith the process is objectively right, than to worry about the coercion scenario, which seems pretty contrived to me.