It is standard practice by the rust core team to implement as little as possible in the core/stdlib and “bless” 3rd party packages that add otherwise necessary

It is standard practice by the rust core team to implement as little as possible in the core/stdlib and “bless” 3rd party packages that add otherwise necessary functionality. This allows the language to evolve more quickly. Cargo, the package management system is very good, and the resulting binary is compiled (therefore you aren’t thrusting 3rd party dependencies on your end users), so there is far less incentive to avoid 3rd party libraries than there might be in Python for example. Can you parse CLI arguments manually using rust? Of course, but should you?