This sounds really cool. Is there a verification step where you confirm that the right number or identifier was entered for the first payment to someone? That's always one of my biggest concerns and I don't want to enter a number twice as the verification.
The UX is standardized by the Central Bank and they mandate a step showing the name of the person/company associated with that Pix key before you make the payment. So you can always double-check.
Does the format for the ID have a check digit in it? Like IBANs and credit card numbers can both be checked offline by an algorithm to tell you that you've made a typo.
From my reading, the system seems like it's intended to be used with a connected device and scanned/copypasted rather than typed or read over the phone.
You can see how it works in this video, after 3:30 https://www.youtube.com/watch?v=Wvz0Yiss4Go. It's in portuguese, but I think you will understand how the interface works.
Note that it is from a bank app (Nubank), Pix itself is not an app. Other banks have similar interfaces
