Exactly, an account has been created for you anyway and the merchant holds pretty much the same amount of data on you, so I think requiring an account is a good

Exactly, an account has been created for you anyway and the merchant holds pretty much the same amount of data on you, so I think requiring an account is a good thing as then at least you know that a company holds all these records about you. To be clear for online purchases I think it's a nice convenience to be able to buy without requiring an account, but for flights it's an entirely different game, you often need to provide a lot more PII.