Which item is also necessary to enter an Amazon Go store alongside a smartphone?

To enter an Amazon Go store, having an Amazon account is essential in addition to a smartphone. The Amazon Go shopping experience is designed around a seamless technology that integrates with customer accounts. When entering the store, shoppers must scan a QR code generated by their Amazon app, which is linked to their Amazon account. This account is pivotal because it allows the store to track purchases, and automatically charge the customer's preferred payment method on file within that account when they leave the store.

Without an Amazon account, the technology that underpins the shopping experience wouldn't function correctly, as it relies on account-specific information to manage purchases and payments. Therefore, possessing an Amazon account is a necessary step to access and utilize the services offered at Amazon Go stores.