It beats the alternative - pulling in some huge package with lots of little functions, all of which end up in the output. At least you're not loading huge amounts of unreachable code into the running system.
In languages with linkers, the better linkers would discard all unreachable functions. Then came DLLs. Use one function in a DLL/.so, and the whole thing has to be loaded. Go and Rust are usually statically linked, reflecting the fact that pulling in big DLLs was usually a lose. You rarely have two different programs on the same machine using the same DLLs, except for some standard low-level ones such as the C library.
In languages with linkers, the better linkers would discard all unreachable functions. Then came DLLs. Use one function in a DLL/.so, and the whole thing has to be loaded. Go and Rust are usually statically linked, reflecting the fact that pulling in big DLLs was usually a lose. You rarely have two different programs on the same machine using the same DLLs, except for some standard low-level ones such as the C library.