Don't expect to buy everything you'd normally find in a convenience store. Recode likens it to a more elaborate Pret A Manger with ready-to-eat meals as well as drinks, meat, produce, snacks and Amazon's own meal kits. The main allure, of course, is the speed. You can walk in, grab a veggie wrap and walk out in a matter of seconds.

There aren't any concrete plans for additional Go stores, and that will likely depend on how well the technology works. How will the AI cope with a busy store, or the inevitable moments when customers have second thoughts and put a product back on the wrong shelf? If it does work, though, it could justify the fears of Walmart and others that have been testing cashier-free stores as a counter to Amazon's expected strategy. It's hard enough for conventional retailers to draw you in when you can order many things straight from Amazon -- they'll face an even tougher battle if Amazon can bring that simplicity to the need-it-now world of retail.