You can just do this with Flask or other frameworks/servers that support auto-restart
(yes I think some js frameworks also allow this)
(yes I think some js frameworks also allow this)
I don't like having a different webserver in development and production.
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PHP does it the right way: Only when a request that touches outdated code hits the server is that outdated code reparsed.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.
But hey if using what you use does what you want, then you do you.