Although i find myself agreeing to Woz's point of view.(Maybe because i submit sites to directories everyday).
1) Meta keywords helps Professional SEO's like me to keep a list of major keywords for each website. This saves time in those innumerous directories which require their own set of keywords (which we have to submit along with site details).
2) They also help me to showcase the keywords to my Potential Clients. I can give them the url and tell them to look at the Meta Keyword Tag to look at the keywords i was targetting, and the subsequent results which i achieved.
3) As Woz said it also helps the Editor of the Directories in categorizing the site.
Some people say who cares of small directories? We only care for Google. My answer is even Google likes backlinks from directories. And if you are submitting to small directories then why not have a list of Keywords in hand in the form of Meta Keyword Tag on your website.