Does Amex Streaming Credit works on all Amazon Digital Download purchases? It works for Playstation Now

I heard a rumor that this new streaming credit applied to non Kindle digital purchases on Amazon. This is important because unlike other digital purchases on Amazon, you run through regular checkout and this allows you to exclude using your gift card balance. This makes it easier to spend this credit in a pinch at the end of the month.

Playstation Now is Sony’s game subscription and streaming service. It is not to be confused with Playstation Plus which is required to play online.

• Discount: Sony is selling the annual Playstation Now subscription everywhere at a discounted rate of $41.99 from the regular price of $59.99. Amex is also offering a $20 monthly credit for specific US streaming subscriptions. It seems to be working for digital purchases at these services
• Payment: Amex Personal Platinum Card, Amazon Gift Card Balance

Estimated Total: $59.99 – 18.00 (sale price of 41.99) + 4.30 (tax) – 5.60 (Amex Streaming Credit) = $40.69

Improvements: You could make the purchase completely with the Amex Platinum Card and have $20 reimbursed. However, Amazon purchases can be discounted by using a card that has 5% rewards (Amazon Prime, Chase Freedom Quarter Bonus, Discover Quarter Bonus, etc) or by buying Amazon gift cards at the grocery store and using a high rewards card (4x to 6x). Your actual savings from the credit are eroded by the amount you would have saved anyways paying with a different method

Do test buys before a major purchase