Using cargo (the build tool), you can add dependencies using Git URLs. Referencing crates.io is just "the usual way" to add dependencies. Git repositories can d

Using cargo (the build tool), you can add dependencies using Git URLs. Referencing crates.io is just "the usual way" to add dependencies. Git repositories can disappear (becoming private, author changes username, etc.), crates.io is more resilient than the average OSS project repo. Most people use one of a handful of Git hosts anyway (GitHub, GitLab, ...) so Git dependencies are still like a huge centralized repo.