Here an explanation from robosats, why not use/accept Amazon Gift Cards from a Shop (Codecard):

Amazon eGift Cards

Amazon eGift Cards are one of the more private payment methods on RoboSats. They tend to be quick and convenient, but funds must be spent on Amazon.

It is important to not share a giftcard code directly on the chat, as this might lead to difficult to solve disputes in case of fraud. As a seller, do not accept a giftcard code on the chat. Instead, the seller should provide an email in chat. The buyer should buy a new giftcard explicitly for the trade and have it sent to the email address of the seller. This way the seller knows he is the only one to have access to the redemeable code. This apprach also generates verifiable evidence that the giftcard was bought for the RoboSats trade in case of dispute.