Ecommerce categories are setup from Sales/Configuration/Product Variants (?!?)/ Public Product Categories - this only defines the structure of the categories - there is no ability yet to add description or content as yet.

As pointed out here:- https://www.odoo.com/forum/Help-1/question/Category-content-on-webstore-55062 despite Odoo's target of being able to edit all website content from the front end at present shop/category/keyboards and shop/category/monitors all generate the same webpage so keyboard specific content placed here will appear on monitor pages also (and vice versa) - we have to hope that this is changed soon or there will be no way to describe individual categories to users, optimise for SEO, show beautiful images, drive sales through marketing different categories in different ways, etc, etc.

Some feedback from Odoo on this point would be most helpful.

"Some feedback from Odoo on this point would be most helpful."

Currently i cannot observe a way to add category specific text or blocks. This feature would surely be of importance.

Did you noticed that you can add product categories through the customize menu when you are in the shop? But categories should be edited from the backbend. I don't think it exists a module to edit categories from the frontend.

Me, too, i think categories or taxonomies (seems drupal got that well very early) are very important concept of information architecture in general. This is not just about having menus, but also important to order elements in any context, or have a chance to summarise many elements of same kind and this counts equal for products as for any pages. It definitively makes SEO a lot easier, hence categories are the most natural way of tagging. They also would build the base of breadcrumb navigation, which could give web-builder a usability boost. And finally they could be natural trigger to show content depending on context, no to fall short in comparison all common CMS. Please update! 

I use a lot of public categories, a expandable list will be really usefull for me.