I am an SEO consultant with 15 years experience. I have seen the evolution of search engines (lets face it when people talk about SEO and Search they are talking about Google).
Today modern algorithms are getting better at understanding natural language queries. So instead of just words they can determine the intent of the searcher, more specifically understand concepts and entities.
This is good for the casual website owner who wants to rank a webpage.
I shall give you an Example. My site is targeted towards the concept of “SEO Experts” take a look seopremo.co.uk
Now in order to rank for Expert I can use language such as “knowledge,know, knowing, understand, understanding,”
to send topical relevancy signals to google. This is not just synonyms of the word expert, but broadening the pages footprint or relationship with the idea of expert.
This means that when someone asks the question “what is an SEO expert” , I can reply with conversational tones to my writing,
“An SEO specialist is someone who has a deep knowledge of statistical relationships between concepts, entities and words.”
as if I was a “person” replying not a computer algorithm.