I don't find it a viable project. Well if its with regular fiat currency, then its okay, and the system is there in almost all countries, where they can pay through certain apps, sometimes these apps provided by the bank itself.
But think of a scenario of paying with cryptocurrencies. The pump delivers the fuel, you send the cryptos, but will have to wait for the confirmation A rude pump employee may not let your wheels roll unless there is a certain number of confirmations and your gf sitting in the car is getting impatient for her shopping