I've noticed that they can click on categories and read the entries there but they usually don't see when there are subcategories.
For instance, if they use a category that only has subcategories but no entries, they tell me that it is empty and they don't find the info they are looking for. So I guess they never see subcategories even in categories which have entries.

Would it be possible to add at the top of the entries, the list of subcategories? Something like how they are displayed in the "show all categories" option would be fine.