All internet sites are HTML sites. WordPress consists of PHP code that creates HTML files as their output. As a website visitor, you cannot see the PHP code. You can only see the HTML code, that your browser translates into visually appealing pages.
We can recover the HTML files. However, the original WordPress installation and dashboard, which you can access via /wp-admin/ is part of the backend. By definition, website visitors and webscrapers cannot see the backend.
Our WordPress version is a reverse-engineered HTML-to-WordPress conversion, based on our HTML version.
If a site was originally built with WordPress, then you do not necessarily need to order the HTML-to-WordPress conversion. You can simply use only the HTML output of the original WP installation. However, if you want to edit the pages with the visual editor in the WordPress dashboard, then you need the HTML-to-WordPress conversion.