I won't mention much as swedal, Jim and the others have covered most of it. You have to consider who is browsing through general directories. BOTW is a large general directory and I personally have never used it to find sites. I use google for that purpose. However I have many times come across sports and games directories and browsed them to find sites that I can personally find interesting. In my opinion if you want to offer submitters traffic and backlinks, a niche directory would be the way forward.
Jamie, thanks. "Sermon Central" is obviously a niche keyword, not one broadly applicable to the internet in general. That being said, the phrase still generates 277 daily searches on the internet. From that I derived 905 unique visitors last month. That places "sermon central" as my #1 keyword out of last month's 35,658 search engine-based visitors. So the positive is that I am getting nearly a thousand highly-focused, targeted visitors each month from that keyword phrase.
you cannot submit your website to directories thinking that your only traffic will be the one from them. The traffic from the search engines is what you should take care of more.