I built out a site using headless WP with Next.js as the frontend. With server side rendering of React, we still took advantage of caching the HTML in a CDN like you would with vanilla WP but it was much easier to build our own theme as desired with React.
While configuring certain parts of Wordpress was tricky at times, especially because deploying it is at odds with the stateless nature of modern containerized infra. Particularly plug-in installation with WP cli requirng a DB connection which makes it tough to fully configure your installation at container build time. I still think it struck a balance between developer experience and a good experience for the content team.
We didn't use it initially because the site was built before they launched that feature, but it definitely reduced some of the boilerplate that we had to write ourselves to wire up Next to WP.
We had already setup a preview page that was wired up to the Wordpress Admin's Preview button that used the endpoint provided by WP to preview content in our UI.
While configuring certain parts of Wordpress was tricky at times, especially because deploying it is at odds with the stateless nature of modern containerized infra. Particularly plug-in installation with WP cli requirng a DB connection which makes it tough to fully configure your installation at container build time. I still think it struck a balance between developer experience and a good experience for the content team.