John Gruber, linking to Chance Miller at 9to5Mac, on why Walmart still refuses to accept Apple Pay:

Using Walmart Pay gives Walmart more information than a regular credit or debit card transaction does.

It's not about fees. Apple Pay costs retailers nothing; Apple takes a small cut from the issuing banks, not the merchant. It's about data. Walmart's terminals support contactless payments. They disabled NFC anyway. Walmart Pay links every transaction to your account. Apple Pay doesn't. Your real card number never touches the merchant's system.

Apple Pay is one of the rare cases where the privacy-preserving option is also the simplest one. Tap your phone, or better yet, your watch. No app, no QR code, no account. I've had this conversation with family and friends more times than I can count, and most of them nod and keep swiping their debit card. Walmart is betting that's how most of their customers behave too, and they're probably right.