Yes, Amazon requires your Affiliate Credentials for importing products from their site. Linksis therefore uses your Credentials to make API calls to Amazon in order to retrieve all the product information.
See how to get your Amazon Affiliate Credentials here.
Note. For product importation, only your Affiliate Tag is required, however to use other features in the app such as bulk import, smart search and product reviews, Linksis rquires your full Amazon Credentials.