I don't understand the use of it !!!

Question

So, while learning HTML5, we've that lesson about the article, aside and section tags
They said that they're for sperating some contents from the main one.
However, what I can't understand is why do we need these three types ? And even for <nav>, we can just put some links and that's all!!!
So please help understanding that by giving some examples of their real use (they said that they are useful for a search engine...how is that ??)?

Answer 1

Abdoul Hakim thnx a lot
Now, I understand their use !!

Answer 2

Hi Feres Daghrour,
<nav>, <aside>, <section> are all basically <div>. What makes them different from the common <div> is their sematical meaning. The semantical meaning helps the SE to understand how the website is structured and depending on that the SE decides to give the website an higher or lower ranking. For normal users still make these tags no sense , but they are very important expecially for people using screen readers. Most of them are blind or visual impaired and can't fully understand, how the website is structured unless there's a screen reader telling them eg."This is a section", "This is an article" a n so on....
Even if your not planning to use your website for these reasons, these tags can help you or other programmers understand how the websited is structured , what should the website display and maybe how.
I hope you understand