Don't get me wrong, Swift is OSS and there are things you can do with it apart from front-end dev, but there are usually better options out there for those other things. For example if I want an HTTP server, I'd choose JS, Kotlin, Rust, etc.

Swift only treats Apple OSes as first class citizens - even though technically you can use it on other platforms it's a painful and limited experience.

A programming language itself isn’t a marketable skill!

Learn the underlying concepts of programming and how computers work and you’ll be able to move from language/framework to pretty much any language/framework easily.

There's a recent Rust ML framework called "burn". So maybe there's also a future for ML in Rust for you.

If you want to train your neural nets you can maybe check out: https://github.com/rust-ml/linfa https://github.com/param087/swiftML (Rust seems to have more active support in terms of libraries)

If you want to integrate ML into an IOS/MacOs app: https://developer.apple.com/documentation/coreml

For userland apps Swift would be better and for training or just being generally being more useful in the future go for Rust.

At the end of the day just choose the language that is more enjoyable for you.

Honestly - now that you know one language learning any new language is a pretty simple task. For example - here's a hello world in the three languages:

# Python
print("Hello, World!")

// Swift
print("Hello, World!")

// Rust
fn main() {
    println!("Hello, World!");
}

As you can see, the differences between Swift and Python are pretty minimal* and while rust adds a whole bunch of extra busywork (you need a function, you need an explanation point, you need a semicolon...) it's generally the same thing.

(*) While that comparison of Python/Swift only differs in the comments, Swift is generally a much more complex language than Python, so you will need to learn a bunch of new concepts. For example if you needed to manually specify the output string encoding you'd write the Swift hello world like this:

let string = "Hello, World!"
if let data = string.data(using: .utf16) {
    print(data)
}

There are some common Swift language patterns there that are rare in other languages:

• if let will gracefully handle any errors that occur in the encoding step (there can't be any errors when you're using utf16 encoding, but if another encoding format was specified it might fail if, for example, you gave it an emoji.
• Swift allows you to interleave part of your function names in between the function arguments. That's not a data() function, the function name is data(using:) and there are other function names that start with data() but accept totally different arguments, for example you might give it a URL and it would download the contents of the URL as the contents of the data.
• the .utf16 syntax is also something I haven't seen elsewhere. The using parameter only accepts String.Encoding.something and you can shortcut that by only writing the .something part.

For completeness, in python and rust you would do:

# python
string = "Hello, World!"
utf16_data = string.encode("utf-16")
print(utf16_data)

# rust
fn main() {
    let string = "Hello, World!";
    let utf16_data: Vec< u16 > = string.encode_utf16().collect();
    println!("{:?}", utf16_data);
}

That's actually pretty good comparison of the three languages and an example of why I like Swift.

The syntax in Rust is absurdly complicated for such a simple task. And while the Python code is very simple, it doesn't handle potential encoding errors as gracefully as Swift, and it also uses a string to specify the encoding, which opens up potential mistakes if you make a simple typo an also you'll have to do a Google search to check - is it "utf-16" or "utf16"? With Swift the correct encoding string will auto-complete and it will fail to compile if you make a mistake.

The tricky part isn’t the syntax, it's the domain knowledge. Well, actually it's syntax, too. Swift has a whole lot of things that aren’t like anything else with sprinkles of Objective-C. Rust turns the common patterns upside down because they make borrow checker sad. But, in the end, what makes you a good engineer is knowing how to apply the tool to solve the problem and that goes well beyond syntax.

Programming languages are like different kinds of saws: all of them are made to cut things, but there are nuances. Some are replaceable, others can be used for one specific thing. Knowing how to operate a hacksaw gives you some idea how a chainsaw would work even though they are fundamentally different. But tinkle it this way: what are you trying to do? Answering that will tell you which saw you need to use.

What are your thoughts on it?