This is probably one of the banking habits that will surprise newcomers the most.
In Vietnam, paying and transferring via QR code is extremely convenient.
In many shops, cafes, or restaurants, you just need to open your banking app, scan the merchant's QR code, verify the recipient, and confirm the payment.
It also works very well between individuals.
Someone covers your restaurant bill?
They can send you their banking QR code.
You scan → enter the amount → confirm.
This is one of the reasons why having a Vietnamese bank account truly changes daily life.