iirc one of the Asian languages pronounces the number 4 as “ha” so instead of typing things like “LOL” they’ll just spam 4 to respond to something funny.
The parenthesis thing is probably something similar. We’ve all got weird linguistic quirks; the digital era just dumps fuel on the fire.
It’s not an actual ball though. Nor is it usually operated with a foot, with a few isolated exceptions per game.
Turns out we’ve been calling it the wrong thing all along!