Checking your content benefits your website's SEO by making sure it meets the standard of search engines and is optimized for visibility. It also helps maintain it's relevance and attract organic traffic and backlinks. The bounce rate will be reduced as you're improving user experience with high quality content, which will make users stay longer on your website, signalling authority to search engines.
By addressing thin content, you provide users with more valuable information, which will increase engagement and the time users spend on your website.