As from my experience in SEO and Links and Directory Submission work, i have seen that most of the client says that Directory Submission turned out very usefull!
In actual, the directory can be general directories, but the category where is site listed via Directory Submission, that category have more sites related to casino, gambling etc…..So the page becomes almost theme based and that link is counted as quality theme based link, secondly that these directories have almost separate IP’s and datacenters, thats the second advantage of the link from these Directories.
In some cases, i have seen saying the clients that they assume 30% OFF-PAGE SEO is done via the Directory Submisison, rest is links building, articles etc….