Earlier quoted context omitted.
You use your bank's phone app. You can scan a QR code or you can send money to someone if you know their "id string", like a phone number, an email or a random string of numbers - you choose the "id string" format you want, and you can have different "ids" linked to different bank accounts. There are no physical cards.
What happens if you miss-type the email or phone number when making a payment? Is there any confirmation of the persons name?
I really dislike the lack of a more anonymous way to transfer money but given how prevalent scams are here I feel like there was no better option.
Also, before PIX bank transfers required a person's full name, full CPF number, full account and branch numbers so arguably PIX is helping to improve privacy a little bit.
However the big issue is when people register their phone numbers as PIX keys because it means strangers can easily get full names from phone numbers.