WP Rocket also have it’s own self-hosted crawler bot that will visit your site and generate cached the files so that when human visitors come to your site, they immediately get the fast, cached version of the page. We also have a sitemap preload feature.
A fast site is important primarily for visitors who may leave a website that is too slow, but also for SEO performance since search engines consider website speed as a ranking factor. The cache files for each web page are generated when the first visitor hits that page. Once generated, all following visitors receive the faster, cached versions of the pages.