Some of the people behind 'wijvertrouwenstemcomputersniet' (we do not trust voting computers) are active in the CCC and have some pretty good arguments on why electronic voting really is a danger to democracy.
https://www.ccc.de/en/tags/wahlcomputer
The link between electronic voting and online voting is a strong one and one would expect the online voting situation to be far more suspect to all kinds of trickery than the one where the voting computer is set up in a booth. Even so, there are some unique ways in which a voting computer in a booth might be manipulated to give incorrect results that do not apply to online voting, but I don't think it matters much, as soon as it's just bits & bytes and audit trails who watches the watchers becomes the real issue.
Any voting system without anonymity and a way to do a re-count and some physical proof is fundamentally broken.