FrankenPHP will perform better than php-fpm though, in worker mode, because it doesn't need to bootstrap fully on every request. In the conference slides, Kevin showed php-fpm had a 12ms request latency, whereas FrankenPHP had 3ms.

But yes, the supervisor plugin is definitely nice to be able to wrap up Caddy + php-fpm in a single container. Makes shipping it easier, especially with the PHP code (because both Caddy and php-fpm need access to the code; Caddy so it can serve static files and check for the existence of PHP files, and php-fpm to actually run your code).

So, not for everyone, especially when you have to manage your own binary.

No one can feel 0.01s faster load time and there will be a dozen more things to tune in your app than shave that tiny bit off.

There's really not much to manage. It's not in any way a challenge, especially if you ship it as a Docker container.

It's true it's probably not for everyone though; the worker mode will not work with legacy apps that heavily use globals and statics, and works best with frameworks that have infrastructure in place to reset in-memory state on each request. Symfony and Laravel are set up for this, for example. API Platform as well, which the author of FrankenPHP himself authored.

The decreased latency means you can serve more requests with the same hardware, with less of an energy cost. That's a win-win. It's not simply about the user experience.

Also remember that loading a webpage often takes many requests. Every little bit shaved off of one request is multiplied. Add onto this that it supports 103 Early Hints which can tell the client to start loading static assets ahead of time, this dramatically reduces total page load times because it avoids the cascade (i.e. browser needing to wait to read the HTML to know what JS/CSS to load). That definitely has a noticeable effect to users.