Attribute categories group the features to be chosen by your customers when adding to cart.
For example for a clothing store you could have categories "Color" and "Size" so your customers will be able to choose a desired combination at the time of purchase for example a Blouse Size XS, Color Red.
Or for a technology store you could have categories like "Color" and "Capacity" so your customers can choose for example a Black USB Flash Drive with 20GB Capacity.
Note: If your products do not have variations or are digital you do not need to create categories or attributes.
