I use yargs and find the API very powerful for complex CLI apps.
This one is superfast but feature-wise it's more comparable to minimist than yargs. Nothing wrong with it but it's not an apple to apple comparison. Great job with the performance though.
Yeah, there was a couple of improvements in readme that was released as patch and the CLI was introduced in a minor release due to not affecting any other functionality (per semver spec). I had some time during the holiday season to implement these features and the fact that the version number increased quickly was mainly due to how semver works and the fact that I had enough time to implement CLI.