I know this... my point was in that Rust didn't have this feature 5-8 years ago when I first started reading/learning about it. A lot of languages haven't had an active scripting-capable usage that can do this until fairly recently. C# even has it in .Net 10, though I'm not sure about dependency handling in that case.
I like and was commenting that rust has the cargo frontmatter instead of a separate cargo file, same for deno in that it can reference the repo/url directly instead of requiring a separate modules file/folder (like node package.json/node_modules) or even with python. You can reference the modules you need directly.
I remember when I saw this in F# interactive (C# didn't have a REPL at all at the time) when I first started using that language around 10 years ago. I thought it was immediately useful as a easy to write, but static typed Python replacement without all of Pythons dependency headaches for quick scripts. Because back then as compared to say C#/Java which required a lot of class files, boilerplate, etc F# read more like a scripting language which made it more suited to this. When they added the ability to pull in packages/dependencies inside the script directly that was great as well. e.g. Pull in a type provider, parse some JSON, make some API calls, create quick CSV's, whatever. Useful for quick scripts, data mangling or quick prototypes - you could just cut and paste the single script with a shebang, message it to someone on your team and it would run dependencies and all without the equivalent venv issues with a simple pasting into a text file. Install .NET SDK and that's it - it would run. In the team I was in at the time it was a quick productivity boost - seeing features implemented in quick scripts and seeing the data workable in a REPL session which could then could be promoted to an actual project was a great workflow.
I think those features have since spread to C# interactive (probably inspired by the F# incubator IMO), as that language has done things to simplify its syntax to make single file apps easier. From your comment Rust seems to be taking a similar approach.
A bunch of third-party Python package manager clients, most famously uv, support this now. They all use the same front-matter format (PEP 723). Unfortunately, pip (the first-party package manager client that's usually distributed with Python) doesn't support it yet: https://github.com/pypa/pip/issues/12891
Interesting... I'm not really involved in much/any Python development, but cool to know there are options out there. I've mostly just run existing projects as needed.
To be precise, Rust files have supported shebangs since well before 1.0, there just wasn't really any built-in tool to point the shebang at. The new stuff in the relevant RFC is actually about Cargo, not Rust; the "Cargo frontmatter" syntax doesn't need to be added to Rust, it can just be stripped by Cargo before it hands off the file to rustc.
I like and was commenting that rust has the cargo frontmatter instead of a separate cargo file, same for deno in that it can reference the repo/url directly instead of requiring a separate modules file/folder (like node package.json/node_modules) or even with python. You can reference the modules you need directly.