I was simply pointing out to you, that there is already an option that sets the Meta Description tag for the Showcase Index page for SEO purposes (which is part of what you are looking for). That is something you can do now (and probably should if you care about SEO).
I've not marked this as "Not considered", however, I doubt that I will implement it when there are ways to add content blocks via the XF Widget System and an HTML widget.
Example... you can easily create an HTML widget and either use the widget display location "Showcase index: Above Items" to display that widget directly above the Items list on Showcase Index, OR you can edit the xa_sc_index template and add the widget key (for that HTML widget) to the index template so that is displays exactly where you want it to display on the index page.
As mentioned, showcase has a widget position on Showcase INDEX (both standard index and modular index).
This literally only takes a couple minutes to add. Here I created an HTML widget and added it to the display position "Showcase index: Above items"
As you can see, the Widget on the index page displays in the same exact location as the "Category Content Block" is displayed on Category pages.
Note: The Category Content block does NOT do ANYTHING for SEO purposes. Categories have a "description" field and that is what is used to set the META DESCRIPTION, not the content within the Category Content Block.
