I recently bought a camera from Amazon during prime sale.
My hdfc card is a basic one and I have some previous order cb pending, so the per month 5%max cb limit on my card was less than total I would have got for buying from smartbuy. So I took 3 months emi offer as hdfc give cb on no cost/cost emi too. This was minimum emi plan available.
Total order was 47-48k something I don't remember exactly.
Cb I got
2400 as 5%cb smartbuy (credited monthly as per emi amount)
1750 prime day offer instant discount.
750 extra on emi txn as amz gift voucher (after 90 days so I will be lucky if I get it)
Edit:Also additional 500 for 50k quarterly spending milestone. Have to wait to see when spending is calculated.
For bill payments big amount or swiggy uber etc I think we can buy amz gv at 5% discount. I don't really need to do this so not sure. You can also get little extra from uber , swiggy etc for using amz pay.
Best part is all your cb is adjusted against statement in next cycle.
I think hdfc still matches or offer better deal than icici during sales.