Well, first of all, because keywords are one of the most important and necessary indicators to evaluate the effectiveness of search engine optimization efforts. If you want to effectively and efficiently promote your site, then be prepared for the fact that you will definitely have to check the relevance of all the pages of your site to those or other words or phrases by which they are found by the user in search engines. And you can check this with the help of this device to the keywords rank checker https://pr-cy.io/tools/keywords-rank-checker/ .