"Reward categories" refers to different groups or types of rewards that can be earned or received. It is a way of organizing or classifying rewards based on their characteristics or benefits. Full definition
The ranking of rewards categories still has the same ordering — with hotel rewards being most profitable, followed by travel and airline. (valuepenguin.com)
3 % Cash Back: You'll earn 3 % Cash Back rewards for each $ 1 spent on purchases in the following rewards categories: gas stations and restaurants. (aarpcreditcard.com)
This is especially good for those who have very varied spending, and don't shop at traditional credit card rewards categories. (valuepenguin.com)