Why do cats like cardboard boxes?
odor
Before being domesticated, cats actually loved climbing trees, using their sharp claws to quickly scale the heights, which gave them a sense of security. The cardboard box had a woody smell, which the cat would inevitably scratch (the same principle applies to scratching posts).
structure
A cardboard box with only one side open is like a very safe and secure nest for a cat, which is why they love to crawl into it. 
sound
As you've probably noticed, whether it's a cat licking a plastic bag or us handling a bag ourselves, it makes a crisp sound. This is like a new toy for a bored cat.
Food residue
We use plastic bags to hold all sorts of things, and bags that have held food, especially small fish, are particularly attractive to cats (which explains why they sometimes rummage through trash cans).
Balls of fluff
Cats love to lick their fur, and the accumulation of hairballs can cause them to eat non-food items. In this case, it's recommended to give them nutritional supplements or hairball remedies to help remove hairballs and supplement any missing micronutrients.
