An idea how to get merchants to accept cryptocurrency

Hello everyone.

Today an idea popped up in my head, and I want to tell you all about it and hear what you think.
I think payment processors like Bitpay etc. can make it convenient for merchants because they can receive fiat and pay their bills without worrying about fluctuations in the price of the cryptocurrencies.
If a merchant want to accept in POS they have to either have a smartphone or PC to show a QR code and confirm the payment. It is easy but I think it can be easier, but with some potential risks and that is one reason why I want your opinions.

What about: a QR code in the shop that people would scan with a normal QR code scanner. This QR code includes a link to a webpage, the IBAN number, the name of the shop and the fiat currency they want to receive the payment in. The IBAN number could be encrypted so that only the payment processor knows it and it can't be known to everyone. No registration required, just a QR code in the shop, and they can still receive fiat if they want.
On the webpage the customer press the amount they have to pay in fiat, their wallets will then be launched with the amount in the crypto they want to pay in. They confirm the payment in their wallet and go back to the webpage, which will say for example: "The payment of $5 to Burger King has been confirmed". They show it to the staff and they will confirm the amount is the right one.
The payment processor (which could be the same one as developed this system) would pay out the merchant once a day, maybe.

I see two problems here: the ability for the merchant to keep track and prove payments have occurred in case of technological failure of some sort and then maybe fraud made by the customer (this could be a self produced webpage which shows a payment has been confirmed).

What do you think?