Mail is scanned and archived anyway, and has been for years. This service merely let's you see the images they already have on hand. It costs not very much extra to add a customer side to an already existing system.
It's useful for people whose mailbox is down the street and it's useful to know if your mail is getting misdirected.
I signed up for it after my letter carrier misdelivered two pieces of my mail in less than two weeks after having maybe one mistake in the previous decade. I think my post office stopped using the same carrier on the same route everyday and instead tried some sort of "load-balancing" scheme where a carrier's route can change based on mail volumes.
By seeing the mail I should be receiving, I know to talk to m neighbors if it doesn't show up in my box within the next day or two. We continue to have delivery issues about every couple of months.
I think this is intended to improve reliability. Having an image taken at some point in the process can identify issues pre and post sort. Maybe even provide evidence that mail was postmarked at a specific time.
It solves the problem of wasted energy delivering mail people don't want, like junk mail/spam. I'd be very interested to see how much wasted paper and gas goes into producing and delivering junk mail. Mail processing centers already use computer vision to see where a parcel's going instead of manually sorting, so this is a logical step forward.
>It solves the problem of wasted energy delivering mail people don't want, like junk mail/spam.
Even if that was true, which it isn't as far as I can tell, that would be counter to the USPS's goals. They make a lot of their money delivering junk mail.
I also don't know what problem this really solves. Grasping at straws for the USPS to remain relevant I think. Big waste of money in my opinion.