I don't subscribe to the concern of wide spread voter fraud but I do have some observations.
It’s literally absentee voting on a wider scale.
True but just because something works on a small scale doesn't automatically mean it translates to a large scale
When I vote in person I insert my ballot in a machine that "whisks it away" and presumably records my vote.
I just voted absentee early this week. What I had looked like a normal in person ballot. I inserted it in a sort of privacy sleeve like you get in person before placing it in the mail in envelope. What happens with my ballot after that I don't know. But its completely possible for someone at the other end to look at my ballot before inserting it in a machine. Nothing I see would stop them other than a sense of morality or peer pressure from another employee/volunteer. Then I suppose if they were inclined they could void my vote with a couple quick marks on my ballot before inserting it.
Hopefully there is some sort of "checks and balances" but what are they?
An added observation locally is the Southfield City Clerk is facing several felonies related to misconduct during the 2018 election. We are told the election results were not affected and the votes were all fairly counted. That may very well be true. But when someone gets caught doing something bad there is a popular mantra that sort of goes
"That may be the first time they were caught but you know it wasn't the first time they did it".