The "what's in it for us" is the crucial part i.e. the back link which is a link in your "resource box" and a possible reputation enhancement as an expert in your niche. The link can be say a direct link to your site with keyword anchor text and a link based on you as the author.
Your article should ideally make the reader compelled to visit your blog for more info. on your topic as well as you trying to get some SEO benefit from the link.
It's best to first publish your best articles to your own site and only post a cut-down version of the post to directories to satisfy their minimum requirements such as 300 characters and original text etc. Study what the prolific article authors do for some ideas such as bullet-point articles.