The "Full Site Editor" is the next evolution in WordPress, bringing the functionality of the block editor to the entire website.
Update 2022/09/16: The FSE is still very much in development and issuing breaking changing frequently. It will not be ready in 2023 and most likely still not mature by 2024.
We will not be supporting the Full Site Editor until 2024 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 next few years, we'll begin transitioning to the new method.
The biggest issue with the Full Site Editor is that WordPress has been marketed it as "ready to be adopted". This is 99% false.
The Full Site Editor is a shiny toy that developers can play with, and nothing more at this time.
It is absolutely not ready for use on 99% of WordPress sites.
The majority of sites running WordPress are businesses that use WordPress as a tool to achieve a specific business purpose.
The FSE is a developer tool to enable developers to help businesses achieve a business goal (such as earning ad revenue).
But one thing the WordPress team doesn't seem to understand is that stability and reliability are core requirements for websites, and not an after-thought or something to be fixed after the fact.
The 1% use case for the Full Site Editor as of 2022 (and 2023) is for developer-owned sites, large corporations with full-time web development staff, and direct-sales agencies with large staff dedicated to building high-sales-value landing pages that are constantly being A/B tested with high volumes of paid ads. And I think 1% is an extraordinarily generous estimate.
What it is, what it is not
The FSE is fundamentally a pagebuilder.
This is great for 4-5 page brochure-style websites.
This is horrible for food blogs where there are hundreds of posts that require a consistent branding. Blocks and pieces of content must not be changed on a block-by-block or post-by-post basis. This is a major, unfixable long-term maintenance issue and needs to be avoided at all costs.
This is because inconsistent styling and branding can not only cause poor user experience, but with the Google Helpful Content update (+ many other ranking algorithms), negative experiences on one page can negatively impact the entire site.
Can specific pages be edited on a page-by-page and block-by-block basis? Sure. You can modify the about, contact, disclaimer, accessibility policy, etc. to your hearts content.
Note: there are features being worked on that enables more fine-grained control and locking of specific features, but this is very much experimental and nowhere close to being ready.
We do genuinely believe that the Full Site Editor will be a better writing and editing experience for bloggers once it matures (meaning: has 1:1 feature parity with the classic setup and stops breaking). At the current rate of development, this may be around 2025.
What they've done with the block editor has been a big improvement, but it wasn't without some major road bumps. And there continues to be breaking changes.
The FSE is far more complex and involved and affects 10 times more aspects of a site than the post editor.
Feast will be adopting to the FSE way of building sites gradually. Our features tagged with "Modern" are being developed in a way that should be compatible.
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.
We don't expect there to be a single point where it would be beneficial to "install" an FSE theme for the foreseeable future.