I can say for a Russian system which looks similar to me: banks do not charge additional fee (acquiring fee), so it's beneficial for shops and small businesses. It works instantaneously, you don't have to carry your card with you (people now always have phones with them but sometimes forget wallets or cards, also phones are locked and cards can't be locked).
Small business doesn't have to pay for anything but a piece of paper with QR code printed on it.