Not useful - always has outdated versions, the "package directory" is just JSON files that somebody needs to keep up-to-date with upstream releases. I've tried it twice, only because it comes from a big company, but I always go back to Aqua [0], which is the most secure and flexible package management system, mostly relying on GitHub releases, but also supporting Rust crates, Go projects, and even Python packages. Even Mise [1] supports its ecosystem, but Aqua is better. For example, the entire ecosystem, authored by Shunsuke Suzuki [2], now uses his ghtkn [3], which doesn't rely on permanent or long-lived GitHub auth. His ecosystem is marvelous, and he keeps releasing quality new projects constantly [4].
[0]: https://aquaproj.github.io/
[1]: https://aquaproj.github.io/
[2]: https://github.com/suzuki-shunsuke
[3]: https://github.com/suzuki-shunsuke/ghtkn
[4]: https://suzuki-shunsuke.github.io/profile/oss-development/