(sorry, I hate that naming convention too. coming up with names is hard)
Rust already has a handful of command-line argument parsers, but none that I particularly like. Clap feels a tad too bloaty and frameworks based on parsing a help string make me uncomfortable. I found myself implementing my own arg parsing and figured it made more sense to just maintain my own framework and add features as necessary instead of bouncing around trying to find a crate that offers all the features I'm interested in.