I don't disagree with any of that, but it doesn't appear that voting by mail is proving to public satisfaction that it hasn't been compromised in some way either, to the point of the Trump's own son circulating fake propaganda of ballots being burned. Postal votes are only ultra-reliable once delivered to a polling station too, and are rather volatile up until that point. I am sure Trump and his cult of voters will be bemoaning the postal vote and claiming some sort of fraud for years to come.
But even a hybrid of paper-trail and automation would make sense. I was reading a lot of these counts are manual and are not using optical scanners (and from the one time I did election duty in Scotland, it was manual counting). The margin for human error if counting manually would be higher than a machine, and you could feed it through the machine a couple of times to account for error in less time than it would take a group of people to do the same job.
Though I do think speed has become a bit more important after seeing the current circumstances of protesting and intimidation outside of where the counting is taking place.