There are two American Express cards linked to my Amazon account. One displays my Membership Rewards balance, the other does not and has not been auto-enrolled. Instead it offers me the option to link, and displays the terms quoted in my previous reply. I do recall linking one of my cards, a few years ago, for the specific purpose of seeing what the Membership Rewards redemption rate is. I might be able to puzzle out when I did that, but it seems evident that not ALL American Express cards are auto-enrolled, even if one of yours was.
Likewise, I originally linked my Citi ThankYou points account to my Amazon account to see the redemption rate, then de-linked it. I don't remember much about the process.
I do not think I have ever linked a Chase Ultimate Rewards card to my Amazon account, and there is not one listed now.
thank you I have spent a few years designing transactional systems ( albeit in the financial arena for forex) and have some skills when it comes to data analysis and visualization. This is BAD really BAD in my opinion and AMEX should have asked for OVERT permission before agreeing to this. Amazon are responsible people, again in my experience, BUT many a slip twix cup and lip