These big brother like outfits think they can control us. I got furious with Amazon a year ago and closed my online usage of Amazon. It started one day when I was just shopping at the Amazon site. No purchase or checkout on my screen. Amazon flaunted my cashback earnings from my Discover account and I was floored. I had never authorized that, not knowingly. These ‘sleep with each other’ dealings between big box businesses are the biggest risks to data security.
IIRC, if you have Discover as an authorized card on Amazon, you can use your Discover points when shopping there.
Never had any Discover account info ever pop up, even at checkout. In fact, I _think_ I have had to go to *my account* and enable all the login security in order to even check my Amazon points, gift card balance or my Discover Cashback myself.
I use the Discover for small purchases and the Cashback is pretty low. Once a year, I apply it to any outstanding balance.
Lately, my Amazon purchases have been free promotions for Kindle ebooks. I still have some $ on a Kindle gift card from January, so I have been chipping on that, rather than spend anything more. I sub to BookBub, which every day sends me 1-4 Kindle titles in my preferred genres that are free or under $2.