I think it's also different internationally? For eg. in India, I already use credit cards, but there's a lifetime free credit card for Amazon that allows you to earn up to 5%. But without Prime, I earn only 3%. Ofc, this is only worthwhile because I already shop from Amazon without Prime and without the credit card, admittedly, but in my scenario it's far more worthwhile to have Prime than to not, because it pays for itself within a month or two even without me consuming a single piece of media from Amazon (whether it's Prime Video or Prime Music or Audible, etc).
Idk if this exists in every country where Prime exists, but I assume they're just trying to gain more market share in India so it's an option here. 🤷🏾♂️ But it certainly makes it worthwhile for me in my specific case.
They possibly just didn't read past the title lol