Why have so many web directory? As if erverone has a so site,and more and more? why are webmaster interesting it?
Realistically, to get links to our websites. Secondarily, a few (very few) will also bring some decent traffic.
...but mostly just for the links. They aren't what they used to be, but you can control the anchor text, get in good neighborhoods, and, just as a side perk, bury your good links in a sea of minor links to confuse the competition.