When a framework "supports auto-restart", that usually means it has its own webserver for development and the auto-restart is supported when you use that.

I don't like having a different webserver in development and production.

For Python, gunicorn is suitable for production and development use and has a --reload option to reload on changed files. This functionality is framework-independent.

The way I understand the gunicord documentation, this has the same effect as if you set up a script which listens for file changes and restarts the server (or workers) every time a file changes.

That's way less efficient compare to how PHP handles it.

I don't want processes to be killed and new ones to be started every time I change a file.

PHP does it the right way: Only when a request that touches outdated code hits the server is that outdated code reparsed. As long as you just edit files, it uses up no resources at all.

I’ve never switched to the browser and reloaded the page fast enough to “beat” a gunicorn reload after editing a file. So I get not “wanting” a process restart but I don’t get why it’s such a big deal in a practical sense.

But hey if using what you use does what you want, then you do you.