You&#x27;d lose most of the safety. E.g. a lot of the value of Rust comes from ownership tracking, but you can&#x27;t track ownership across a C-ABI boundary because the information simply isn&#x27;t there. And I&#x27;m not sure assurances in libraries used by unsafe languages are really that valuable - it&#x27;d be like locking your back door and leaving your front door open. Better to make a clean break.