HTML or WordPress?

The question is inanimate and shows a lack of understanding and knowledge. First, you can not do the same with pure HTML as with WordPress (databases, templates, functionality, etc.); however, you can create similar solutions using PHP / HTML / Javascript, since WordPress can do more or less what is needed. .

The point is, if you need a site more or less like WordPress, use WordPress. If not, I would probably recommend the custom coding of the page or find other ready-to-use solutions that can meet your needs.

But there is no real difference in "using HTML, or using WordPress": WordPress uses HTML, it shows the information that server-side files send to the user through HTML, CSS and Javascript.