Sure but at some point you might want to create a file and frequently using user input or filter files using some user provided query string, the kind of use ca

Sure but at some point you might want to create a file and frequently using user input or filter files using some user provided query string, the kind of use cases that unicode normalization was invented for. So the whole "opaque blob of bytes" filesystem handling is nice if all you want is to not silently corrupt files, but it is very obviously not even covering 10% of normal use cases. Rust isn't being super smart, it just has its hands thrown up in the air.