This is the "two language problem" ( I would like to hear from people who extensively used Julia by the way, which claims to solve this problem, does it really ?)
It then gives you a bunch of new problems. First and foremost that you now work in a niche language with fewer packages and fewer people who can maintain the code. Then you get the huge JIT latency. And deployment issues. And lack of static tooling which Rust and Python have.
For me, as a research software engineer writing performance sensitive code, those tradeoffs are worth it. For most people, it probably isn’t. But if you’re the kind of person who cares about the Python optimization ladder, you should look into Julia. It’s how I got hooked.
If you then want to access fully trimmed small executables then you have to start writing Julia similarly to how you write rust.
To me the fact that this is even possible blows my mind and I have tons of fun coding in it. Except when precompiling things. That is something that really needs to be addressed.
They're only "fast" compared to slow interpreted languages like Python.