I mean really, think about it. Who really uses link directories to find stuff?? No one. I would say 95% of people use the 3 main search engines. Is this some weird thing from before google and yahoo or something?
It's a quick and easy way to get backlinks. It's a quick and easy way to get backlinks with the anchor text you want. (Although most directories aren't of much value, and it's worth checking that the place you're submitting to is actually indexed itself)
I don't submit any of my sites to directories and they do fine. Most directory link pages are really low PR, so the PR passed through a directory links isn't a great deal. Got better things to do with my time than chase low quality backlinks. The best way by far to gain links is create something webmasters will link to or at least get people talking about your content on forums and social bookmark sites etc... Free stuff is a particularly good way to get links. David Law