Every visitor to a live Elementor page triggers WordPress to boot PHP, query MySQL, run plugin filters, and assemble the page from saved widgets. That's a lot of work to render markup that doesn't change between requests.
A static export does that work once — at export time — and serves the result as plain HTML, CSS, and JS. Visitors get the same page; your server gets nothing to do. Core Web Vitals typically improve substantially because there's no editor runtime, no admin-bar JS, and no jQuery on the critical path.