I personally only tend to use + when there's two or maybe three things at most, in any language, and then switch to an API like this if it exists for more complex things, no matter the language. I find it much easier to read. YMMV.
(And you can use + in Rust, but you'd have to call .to_string() on the integer first)
steve, think I sent you an email before and you responded, but just wanted to say again the Rust Book is a work of art. Since I read it and emailed you, I completed a fairly non-trivial Grad School project entirely in rust. I took a lot of the shortcuts, but the rust book was an excellent primer.
Best intro documentation of any language I have tried to learn recently.