Why Hugo and not Wordpress, Drupal etc?
Hugo is a static site generator. Your website is simply HTML and maybe some JavaScript, but no PHP server site code. There is also no MySQL or whatever database. That results in a much faster pageload. There is also no backend to login to. The backend is so to speak on your PC where you write the code (in Visual Studio Code for example) and upload it. There is no access point for hackers. No CMS code or plugins you need to keep updated.
Why Hugo and not Jeckyll, Gatsby, Eleventy etc?
That’s a personal choice. They are sort of similar in what they are. But Hugo has good recourses, a larger userbase and therefore it’s more easy to get help when you get stuck. Hugo also has a large selection of ready-to-start themes and shortcodes.