One of they key benefits is submitting to quality directories will help get your site into SERP's faster and bring in more quality traffic to your listing and your website! Google tell's you on their page that one of they key ways to move up in search ranking is to have quality one-way links pointing back to your site! It is the necessary evil to submit to as many QUALITY web directories as much as possible to build up not only Search Engine Ranking, but long term and ongoing traffic which then equates to MONEY! and SALES!
You should link your site to this quality directory, they human edit all of the submissions, which make for quality content and good SERPs.
Hope this help you!!