Thanks for the screenshots @Poedagar ! The information Emily shared here is correct. The quick buy button, or sometimes called express checkout button, is a dynamic button that changes the payment option shown based on the customer’s past payment history and browser cookies. As you noted, if you have Shop Promise enabled on your store, then Shop Pay is a prioritized express checkout option. Shop Promise is optional, you can disable it any time through the settings in the Shop sales channel. Doing so would no longer prioritize Shop Pay as an express checkout option.
Let me know if that clarifies this for you.