"Basically what you should do is host your PHP file on your own web server...." It is possible. But, "on my own web server" I can host the game itself. But why then do I need ITCH.IO? For monetization only?
Viewing post in Does itch.io support PHP ?
But why then do I need ITCH.IO?
I mean, you don't. Itch is (from my understanding) mainly designed as a marketplace for games. They host free stuff too because they're cool like that, but they're not really a replacement for a web host. If you're looking for someone to rent you a PHP server this isn't the place for that.