It is also one of off page seo technique it helps to get a quality backlink for the website. Press release submission means any news regarding your company has been outed it can be post in those sites.
Yes, if an company released new product for example, they want to publish short article on some press release websites. If such article is indexed by google and if press release do not require nofollow links in article, then it can bring some SEO value to the company website.