SEO descriptions are like little summaries of what your website is all about. Think of it like short blurbs on the back cover of a book that tell you what the story is about.
These descriptions will help people find your website when they use search engines, just like Google.
When someone types in a search term, like "Churches in London," Google shows them a list of websites that might have the word "Churches in London". The SEO description helps Google understand what the website is about and whether it's a good match for the search term.
So, if a website has a good SEO description that accurately describes what the website is about, it's more likely to show up in the search results when someone types in a related search term.