Pennsylvania counts votes where the signature doesn't match or the postmark is missing or unclear and other (lawd, please forgive me) problematic things.
Even during Obama, the Carter/Baker commission on voting clearly found that the system of just sending out ballots was the worst way to do it. And here we are with it being the DNCs voting method of choice.
Remember, the DNC claims we must do exactly what Faucci says, but we can ignore him as the village idiot when he says that voting in person is safe if masks are required.