Most vanish completely from the shelves within a few months of publication, and are usually pretty hard to find even during those few months. Ghostwriters Unite! The fundamental problem facing any professional writer is finding a steady supply of ideas and subjects so dazzlingly certain to appeal to the book-buying public that publishers are bound to put up huge advances.
Another may want emotionally charged language. This will help attract the right type of clients or just get the buzz out there that you are offering ghostwriting. There is a need out there.
That may mean less impact from a social media perspective, fewer links, less enjoyment and engagement from readers, and these things, directly and indirectly, can negatively affect your SEO. So why do so many writers ghostwrite, and why do so many love it?
Writing a post based on a title and nothing more. You save time This is a clear benefit of ghostwriting, possibly the main benefit.