I have done it in my own personal templates and as Amazon are playing around with Associate ID API requirements I thought this could be a great back door way of getting into the relevant amazon page so we can quickly manually update details.
Thank you for the suggestion. There used to be a [key:amazonLink] but I took it away in 5.0, as I am trying to move users from using Amazon, even though they do have great data and currently hold the monopoly on online shopping. Their Amazon Prime was a brilliant move, given them full dominance over shipping prices. My entire extended family uses them, since they get free shipping now.
Technically many of the templates now use the generic loop to create the fields, so I hate to break that up to add a specific feature for the Amazon link. But you are right that it might prove useful, so I will keep it in mind. Although most power users are likely to be tweaking a customized template.