That does depend on honesty of unobservable USPS activity. So it's not obviously better. Even with USPS honest, people opening the envelopes need policing.

Well, it’s called mail in voting, but they actually have locations around town where you drive up and drop them into a locked box. There are also boxes set up at the library and other places. You can mail them in, but we feel better about dropping them into the box while out and about doing other things.