It's good for sales and for SEO to give Product attributes descriptions. How this would work is that when the attribute is clicked on the product page, a popup opens with the description.

Here is an example from a extremely successful online retailer:

Click on any product attribute to see what I mean.

On category the attribute descriptions are accessible when you click on the 'Explanation' link next to the filter. Example:

The customer uses the attribute description to learn what the attribute means for choosing the right product. For SEO its good because it allows us to add relevant and rich content to the pages. (H2 title, text and image)