Sam’s Club and WalMart are basically the last two major holdouts that do not support Apple Pay. There is no technical reason that they cannot accept Apple Pay at their transaction terminals other than it’s a conscious business decision.
Walmart operates their own payment network. An obvious question might be why? it reduces Walmarts costs processing credit cards and their gift cards. Apple Pay charges the banks, not merchant, a small percentage of each transaction, approximately 15¢ per $100. Google Pay is free.
Google Pay uses tokens, but does share the entire card number with the merchant. Apple Pay does not share the entire card number. I’m sure Sam’s and Walmart are tracking your purchases and sharing (selling) information about your with other businesses. Apple Pay does not permit that. Your personal information is never revealed, except in the case of shipping a product (name, address etc.) when using Apple Pay.
Legal - Apple Pay & Privacy - Apple
https://corporate.walmart.com/privacy-security/walmart-privacy-notice
So, while we may quibble over terms, loss of being able to sell your information for a profit, is penny pinching in my book. 😀