That's part of it, yes. I run a board myself and we created an option for folks to hide specific forums they have no interest in. These forums do not show up in the search results, on the board index, or anywhere else on the site. Think of it as an "opt-in" mechanism to revoke my security access to a specific forum. Unfortunately we don't use the same software or I would offer to help you out with some coding. It's a nice-to-have feature that lets folks tailor the board to their own interests. For example, if I have zero interest in currency collecting, I could "hide" the Paper Money forum.