USPS Informed Delivery

Not a new feature. I've been using it for almost a decade. I believe implementation has been zip code by zip code. Perhaps where you live it only became available recently. We get an e-mail early in the AM letting us know what 1st class mail is expected to be delivered and a second e-mail less than an hour after mail has been delivered to our address letting us know that delivery has been accomplished. Very helpful to see what important mail may be missing from a daily delivery. If it doesn't show up within the next several delivery days, you can flag that item for tracing right on the informed delivery web site.

No, you have not been using the NEW app. Adds new features.

A feature on a smart phone that is unavailable on their web site? For those of us who use our smart phones only when we're required to for 2FA or when out of the house, please describe the new features.

What else do I need to know about my mail other than what I should expect to be delivered and when mail delivery has occurred that warrant cluttering my cell phone with one more app?

Well, golly, I guess you had a hard time looking at what is offered on the web site about it.