The advantage of a CMS cache plugin (example: WP-FastestCache) is that it will put the rendering of the cached page and serve the visitors from this cache. This prevents the server from working to generate the page for each visitor. In return, we must think about purging the cache and configure everything to avoid caching some important pages that must remain unique per visitor.
On the other hand, PageSpeed performs similar manipulations to a CMS type cache plugin but ensures that caches that must remain unique per visitor, remain unique!
In addition, an interesting feature is present: include a hash elements of a page (HTML / CSS / JS) – see reference here.
Here are three tests of the homepage of a WordPress (the homepage included 1 article and the latter had several images).
PageSpeed is the winner on the YSlow Score as well as the Total Page Size. A CMS cache remains a good alternative for web hosts that do not offer server caching tools.
If you use WordPress and PageSpeed does not suit you, we recommend using WP-Rocket.