What is the benefit of directory submission in SEO ?

The only benefit is to get one-way back-link....... but you should not to do in bulk.

Web directories are collections of links which are organized by topic for the convenience of people browsing the Internet looking for information and resources. Using a web directory, Internet users can find lists of websites on related topics which complement each other.

Directory Submission is really very ancient way to get back links but I don't think that it is still effective. We need to get back links from relevant sources.....

by submitting a website link on high pagerank directories we can get quality backlinks to the site as well as some directories will send traffic to the site.

If good quality directory submission is done it surely helps in increasing quality links back to the website in turn increase traffic to the website..

I guess directory submissions are not effective now.