People may see this comment and think it's being standoffish, but it's the truth. What OP wants is a system where you transfer traditional currency into digital money (which you're going to need to use a credit card/bank account at least once to do), and then use that without having to worry about using your card on multiple different websites. This is exactly what Apple Pay/Paypal is, minus the transaction fees. This is not the purpose of cryptocurrencies, nor will it ever be.