I’ve seen people do this and I’m always confused, do they believe they will never have to reason about the code ever again.

I suppose if it is like the Zig Rewrite where essentially all development is being done by Claude, I can imagine this making sense.

But in any other case, you had a codebase that presumably you wrote, you could reason about, you could refactor etc. and then you made it into a completely unintelligible code base, which even if written cleanly will take a long time to reason about. Typescript to Rust is not just syntax changes. It doesn’t make sense to me, unless you believe you will be completely out of the loop in managing this code in the future.