With a lack of adequate hardscape tools in Revit, many firms and individuals have taken to modeling hardscape with a variety of other families. Two of the most popular hardscape alternatives are Floors and Roofs. They are quite similar in their structure and they can both be modified by sub-elements.
When I was first introduced to the concept of modifying sub-elements it was actually via a Roof. As I have seen the topic discussed and presented, it seems like Roofs are quite popular among architects and structural engineers, perhaps because they are more familiar with shape-editing Roofs. But after using both Floors and Roofs for hardscape, I have found Floors to be the better option.
Here are the reasons why I use Floors for my hardscape (and not Roofs):