Writing regular content for your website helps your site to be indexed more regularly by the search engines, but it’s vital that your content is relevant to the themes of your website. Writing content that is off topic for your website will have the adverse effect, and cause your site problems in the SERPs.
Try to think of it as a giant catalogue with an index. Your website exists on one of the pages of the catalogue, and can only be found by the categories in the index. If your website writes about your industry it will show up for searches relating to that industry. If your website writes about numerous different, unrelated things, it won’t show up for anything because it won’t be targeted enough. You won’t have a nice big, bold index listing because your site is impossible to categories by Google.
Keep your content relevant and keep it interesting and regular. By writing about every facet of your industry you’ll ensure that your site becomes an authority for your industry, which will mean better rankings and more links.