I find that RESTfulness improves the quality of design by forcing a little consideration on how to represent resources and actions on resources. The alternative is often littering the API with actions anytime a new one is needed - once that first version is out in the wild, it becomes a lot harder to take the time to consider the design choices. REST gives you a conceptual framework in which to implement new functionality.
In addition, all the consumers get the benefit of a common specification - if you tell me your service is RESTful, I can probably start making requests without even knowing much more than a starting URI, because I know how GET, POST, PUT, and DELETE will behave; I know what the error/success codes are going to look like; I can guess that Content-Type is going to drive the input and Accept will drive the output.
Sure, the consumer is probably going to leap through whatever hoops I put out there if they want my data, but RESTfulness is a courtesy, extending a hand and saying I'm not going to make extra work for you.
In the case of the OP, I'd say "Amazon proves that people who want to use a well-designed and beneficial service will work with whatever they're given".
In addition, all the consumers get the benefit of a common specification - if you tell me your service is RESTful, I can probably start making requests without even knowing much more than a starting URI, because I know how GET, POST, PUT, and DELETE will behave; I know what the error/success codes are going to look like; I can guess that Content-Type is going to drive the input and Accept will drive the output.
Sure, the consumer is probably going to leap through whatever hoops I put out there if they want my data, but RESTfulness is a courtesy, extending a hand and saying I'm not going to make extra work for you.
In the case of the OP, I'd say "Amazon proves that people who want to use a well-designed and beneficial service will work with whatever they're given".