Except for the sick, disabled, elderly, deceased, people overseas or out-of-town, anyone in the military that's deployed, people who don't have good access to transportation, people who work long continuous shifts like healthcare workers and firefighters, poll workers, people in jail awaiting their trials, people with stalkers...

I mean none because Gmail's spam filters are pretty good these days but I take your point. I'm not at all saying people should be trained to vote via unsolicited email. You would have to ask for digital voting when you register. And you would of course be able to check that your ballot was received through the same online form that already exists for mail-in ballots.

Right now you already give election officials your email for mail-in ballots and if there's a problem with your ballot they'll email you!

I think we could do a lot better than this when it comes to online voting but as a baseline optionally replacing the transport from physical mail to email I don't think would be the end of the world.