For parallelism, Modern tooling like TSAN can close the gap somewhat. If you are planning to introduce threads, not testing it with TSAN is silly at best.
If you're writing safe, parallel Rust code, you don't really need to use TSAN. You may hit a deadlock sometimes, but those tend to be easy to figure out in my experience.
The people implementing the libraries you use (e.g. Rayon) may have to use TSAN, of course.
