It’s not just about parentheses, really. It’s about almost anything that a script engine will ruthlessly interpret before executing a command: variable markers (percent signs), redirection symbols, parentheses, double quotes, ampersands…
My most common… let’s say, case, is this:

@echo off

echo Doing something (very important)…

Put this in a BATch file, run it, and you’ll end up with [...]