is it good to use WordPress in the same url extension in terms of seo?

It is true that WordPress stores your page/post content in a database. Every CMS does this, however. Googlebot crawls links so it will see the public or front-end version of the page that WordPress produces at each URL. WordPress will serve up the page content from the database along with the theme/template/css rules in effect on that page.

Bottom line: how you see the final output of your WordPress pages is how Google will crawl them, essentially. Googlebot is not using a browser, for example so it interprets your page differently.

Name your posts with good, descriptive titles and personally I would recommend using the “post name” style for Permalinks. This gives you good keyword-rich URLs.

WP admin > Settings > Permalinks

WordPress is very SEO friendly right out of the box and on-page SEO is a breeze.