A prime comparison is a local employer bussing everyone from their village to the tactically most appropriate voting location and paying them a bit of money and/or alcohol to vote properly - despite being generally illegal, when it happens in a paper ballot system, these people can and do vote as they please anyway. (I recall a case in local municipality elections where there were criminal charges for such actions, but the vote counting in that district showed that most of the bussed-in and paid voters actually voted against the organizer).
Since there is no way for anyone, including themselves, to get to know how their vote went, if the voting stations are run properly, can be monitored by all constesting parties, yadda yadda, we know how to run this process even in cases where the opposing parties are openly hostile and attempt dirty tricks.
In e-voting, there is no good way against this approach, and local "strongmen" are a realistic threat that actually will get used in contested elections if they are able to. They'd have everyone from their factory to either vote in their office with the supervisor watching over the shoulder or get fired, and there's no good way to prevent that from happening.
