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.
The World Slinging Association may beg to differ on the "never became a sport" part: https://www.facebook.com/WorldSlingingAssociation/
I think it’s the same reason there’s no sport of throwing stones at targets but there is a sport of throwing darts at a board. Scoring is harder when the projectile bounces.
Horseshoes, curling, shuffleboard, etc use where the projectile ends up but that’s not a viable option with a slingshot.