It should add some convenience ahead of the busy holiday shopping season, since it makes it easier to see your orders without having to sift through all of your messages.
Gmail will, in the coming weeks, provide a small green indicator in your inbox that shows when a package has shipped and when it’s expected to arrive. If you tap the email, you’ll see more information such as a link to track the package from the shipper and order details. It will also provide the package status with labels that say, for example, “arriving tomorrow” or “delivered today.” It’ll also tell you if there’s a delay.
The option won’t be on by default. Google will provide a pop-up that lets you choose to allow the status updates if you want them. And you can turn it off in settings if you decide you no longer need the notifications.