In addition to reading Swift benchmark code, mixing unsafe C with Swift aren't complicated to learn and offer more performant. In contrast to Adobe AIR + C API (ANE).
Agreed, every languages do established and growth into a mature language. Swift was born and constantly learns every languages for the last 30 years of pros and cons including Rust, Go and Ruby.
Swift is built on LLVM (Compiler designer) and CLang which both are developed by the same group but they do not forget children who can learns Swift from young age for robotics, electronics, 3D and many things could be done with Swift.
More is need to be done on tooling before Swift will be on par as Java and C ecosystem.
In the same analogy, why choose Tesla or electric powered vehicles when other car manufacturers are established? Keep learning and improve it.