The design of service workers is ridiculous! A normal application will check if a file it needs is downloaded, and if not, download it. An insane application

The design of service workers is ridiculous! A normal application will check if a file it needs is downloaded, and if not, download it. An insane application would unconditionally attempt to download the file, except first it forks off a new child process, turns it into a network MITM proxy, and have it intercept the request. Because how else can you access local files on disk except through HTTP?