In theory this is good, but anything which delays the results is a net negative. The delay gives them time to come up with whatever difference they need.
Exactly—this stops them from duplicating ballots but does not stop them from pulling the names from the registered voters who didn’t vote list and voting in their name—
one step forward, two steps back—buys lots of time for the kind of cheating that needs time—makes them work a little harder...
;-)
This is why you need enough in person votes to overcome the margin created by mail in votes.