That round circle or loading type in website

I saw different site that loads faster.But it only load faster after loading a circle start revolve for some second.Is it helpful for SEO or for what purpose it usually used.If it is good for site then i can i make it in my site?
Hope my question is understandable.

The various “loading” icons don’t make sites faster, but they provide feedback to the user when the content is loading so they know that the page isn’t dead.