The part of this that is news to me (I have long known about using the street address of the post office with #BOXNUMBER, and used this to get driver's licenses in the past) is that they will now accept UPS/FedEx shipments to a PO box when addressed in this manner.

For a long time, the USPS would simply refuse to accept deliveries from competitors, which always struck me as the utmost in anticompetitive, non-interoperable-by-design bullshit. I'm glad to hear they have stopped.