The USPS email notification service has been very valuable to me.
And that’s because my mailmen have been a succession of goofballs. Sometimes my mail gets delivered to one house above me. And sometimes it’s to one house below me.
The notification service tells me when I’m missing mail. So I’ve got to put my shoes on, and go talk to the neighbors.
(And, yes, I’ve complained to the local postmaster. Little good that did.)
I got you beat. My post office ran out of stamps and Money orders for over six months last year. You could still mail packages and process visas.