As a reminder, Walmart Pay isn't strictly a competitor for tap-to-pay options like Android Pay or Apple Pay. It's more intended to streamline the checkout process using QR codes. With that said, it's far too soon to tell how well it works in practice. Walmart's service has only been available for about a month and a half in any state, and there just isn't enough data to know whether or not customers will embrace it in earnest.

Update (7/6): And now Walmart says its mobile payment system is available nationwide, in its more than 4,600 stores across the US. According to senior VR Dennis Eckert this is "just the beginning," as the company makes its app a remote control for a faster, more streamlined shopping experience.