Yes, this is definitely one reason. At the time, I was interested in working on Vim, but it's hard to make changes to a C codebase and be confident you won't in

Yes, this is definitely one reason. At the time, I was interested in working on Vim, but it's hard to make changes to a C codebase and be confident you won't introduce segfaults or subtle memory safety issues. Rust's "hack without fear" mantra definitely applied here. :)