I have a couple slings my cousin brought back from Tibet, and a few years ago when I was in Peru I brought some back from there as well (they're called 'huaraca' in Quechua I think). I find it interesting that many cultures used them historically but it never became a sport like archery, javelin, etc., did.
They're very lightweight and are definitely an underrated backpacking tool for keeping marmots at bay when they're attacking your tents and gear, haha.