Having SEO friendly contents will not only support your website SEO but will also give your website visitors enough information to read.
Having 300-400 words of SEO friendly contents on each page of a website could sharply improve your website rankings in the short and long term because Google likes text based information. It is actually very important for the long term establishment of any website because Google algorithms read text. That’s why text information is vital from an SEO point of view.
If people spend more time on your web pages/website, it helps to reduce the Google bounce rate (you can check your website bounce rate via the Google analytics tool). If your website bounce rate is higher it means people are spending less time on your website and it encourages Google to give your website lower rankings.