Cats do that. They entertain themselves by tormenting us.
Seriously, it is an object they can manipulate that moves and makes noise. Bored kitties make their own fun.
If you don’t want your toilet paper unraveled, turn the roll around. If you want your cat to have other things to do, provide them. Many cats love to chase a laser pointer dot, a small toy on a fishing pole, or pretend to kill a stuffed animal.