The "Full Site Editor" is the next evolution in WordPress, bringing the functionality of the block editor to the entire website.
We will not be supporting the Full Site Editor until 2023 at the earliest.
This is because its initial release will be full of bugs, undocumented issues, missing features, and incompatibility with many plugins and themes.
This is highly experimental, BETA-stage software with no real world testing. It should be released as separate, opt-in plugin. Labeling it the "next release" as WordPress 5.9 is a poor decision in our opinion.
Overall, it seems like right now we are rushing things in a dangerous way.https://github.com/WordPress/gutenberg/issues/36556
Also see: the complicated futility of WordPress
There is no benefit to using the Full Site Editor for the foreseeable future. You'll be able to do nothing new or special that the current methods can't.
Your food blog will not be successful because you're using the next shiny new toy. The success of your food blog is determined by your content, and the Full Site Editor currently provides absolutely zero benefit to your content.
Once enough time has passed that the massive number of bugs and issues are reported to the WordPress team and resolved over the first 1-2 years, we'll begin transitioning to the new method.
We do genuinely believe that the Full Site Editor will be a better writing and editing experience for bloggers - in 1-2 (maybe 3) years.
What they've done with the block editor has been a big improvement, but it wasn't without some major road bumps. This FSE is far more complex and involved and affects 10 times more aspects of a site than the post editor.
The Feast Plugin has already made a partial transition to building the site with the Modern Homepage, Modern Sidebar and Modern Footer. This should significantly reduce the amount of work necessary to transition to the Full Site Editor.