Most languages have some sort of peristent/immutable data library available. But that's not the same as having it built in! If you have to weave 3rd party types through the entire application and convert on behalf of libraries that aren't compatible. There is an enormous benefit to having these data structures as first class citizens.

And thank you for highlighting the conceptual link to Rust's borrow checker. Clojure and Rust are far and away my two favorite languages and this largely articulates why: they both have language-level constructs to completely solve the data ownership problem. Not just "here's some tools to optionally solve it, good luck" but truly, fully solve it. Full stop.

Almost every other language leaves ownership enforcement up to the developer. Clojure and Rust take entirely different approaches to virtually everything, but they converge on this one point and it's a crucial one. Types, syntax, compilation models, garbage collection, etc. are all secondary concerns to managed data ownership IMO.