So this sounds just like PayID in Australia or what was payM in the UK (which got shut down a couple of years ago due to lack of use), minus the QR code generation part. It's used between private people to make it easier to send money to one another without having to type in bank account details, but never really used to pay businesses (except under the table). How come this is so popular in Brasil for paying busines…
Brazil adopted banking cards very fast and I remember using them virtually everywhere in debit or credit mode as early as my first card in 2008, I never had to carry money around. But they require two things that are a problem in a Brazil sized country with a Brazil density and infra structure: cell coverage and equipment. So small towns, small shops, independent professionals, etc would not have them or even be able to use them sometimes. Even today there are lots of places with internet but not cell coverage (radio, fiberglass or other infra but no cell tower).
This was changing on its own recently, many companies launched new machines that are cheaper and allow more small vendors to accept cards (+ working over the internet). This is still worse than the free approach of pix (for normal people) and a potentially lower fee for companies. Plus it allows people to buy with something they will have on them way more than their wallet, their phones.
I was in Brazil last week and I had to use pix only a few times to pay: parking (beach lot), tire fix (very small shop on the road) and thats it, everywhere else I used my credit card. Even though they accept pix, its not that huge of a difference for traditional business as far as I can tell, the payment terminal will also facilite pix transactions.
ps. you can tap and pay with pix too! https://support.google.com/googlepay/answer/14615541