But the website and app UX for their credit card is awful. Everything is a hassle.
If you use Amazon a lot you can get 5% back on that (Chase Amazon).
There are also 5% back for certain categories such as eating out, some time limited (Discover, Chase Freedom).
I canceled my Prime membership and instantly the reward rate dropped to 3%, which is a pretty crummy store card. Compare to Target as an example - 5% without the pricey subscription.
You have to buy an insane amount of stuff from Amazon/Whole Foods/Fresh to make that product make sense above and beyond other rewards offerings.
In general cashback on cards isn't going to save you much money, but it's still nice picking up several hundred dollars worth of cashback over the course of a year.
On top of that the article makes the classic mistake of saying it pays for itself if you spend $166 a month, but it only really pays for itself if the marginal value of using the card over a generic 1.5% cashback card on the things you can't get 3% for already is more than $5 a month. Things like high cashback percentages for the first $X a month in specific categories make this intentionally hard to calculate, and are part of why I never really got into optimizing my credit card benefits. It's obnoxiously hard to compare.