Two dozen programming languages shipped in or not, almost no languages support this.

It is something that you start appreciating a lot more once you have used it significantly. It helps a lot with writing more self-documenting interfaces that are legible at a glance.

Another detail I did not mention is that _public names are part of the interface_. This means that two functions that differ only in the public names are distinct overloads.

To give an extremely simple example (taken from Apple's docs):

class Counter {

    var count = 0

    func increment() {
        count += 1
    }
    
    func increment(by amount: Int) {
        count += amount
    }
    ...

}

This starts becoming even more valuable when you have more complex objects, and allows you to move (e.g. on some kind of repository class) mangling of overload names into more readable named argument overloads.