So could Go (https://pkg.go.dev/embed), Rust (https://doc.rust-lang.org/std/macro.include_str.html) and a number of other languages in the set.

this would provide the optimizer the unfair chance to replace the entire application with a compile time constant

The idea of using a file is to force the program to use that number as an unknown value at compile time.

command line arguments would be unknown at compile time.