Why anchor text is necessary?

Anchor text provides the search engine with context for inbound links for which it should rank, this has a direct impact on the organic traffic of the website. With this, an increase in the traffic coming from Search Engines can be seen.

Along with gathering information about the content of the page and what the page is related to from the search engines anchor text, they also see the keywords for which the website has to be ranked. This is a big factor in ranking the website and that is why it plays a big role in link building.