This will clearly hurt them in statewide elections, but I wonder how it plays out in local rural elections. I can imagine the rejected ballots leaning more blue than average in heavily red areas.
I can also imagine the opposite: Older folks have less mobility on average, and are probably more likely to mail the ballots in. The Propublica article doesn't say anything about this, but I imagine some election officials track it.
Their ID requirements in Ohio blew back a similar way a few years ago. They made it extremely hard to vote without a driver's license, thinking it'd hit college kids, but it mostly hit retirees that no longer drive.
* https://www.propublica.org/article/mail-ballot-delays-postal...