I have a Wordpress website with a few posts, but it is rather a website, not a blog - I'm not planning to make any new posts on it. I wonder if it is worth to submit this my site into RSS directories even if I'm not going to make any new posts on this site? Would I get a link from an RSS directory only if I make a new post?
If your page will not be updated, then there is no point of creating RSS feed of it, because feed is something like an "update" of your website or blog and readers expect something new every time they open the reader. Create RSS feed only if you have plans to update your content.
RSS feeds are mostly for those websites that are not updatedon a regularly basis (blogs and the type). If you have a website that will not be updated that often then RSS feeds will not do much benefit.