[Cyph0n]

Just to add to other comments: Cargo feature flags are another reason why you need to build your dependencies.

Of course, if Cargo supported pre-compiled dependencies, I am guessing that it would be smart enough to only recompile the dependencies that are using non-default features.

[Matthias247]

In addition to just feature flags the fact that a lot of Rust code is generic and would only be compiled into binary form in the final application would likely prevent excessive use of precompiled artifacts.