Yes, because as of today, right now, every human on earth could decide to not visit the cinema again and instead download the content off of the internet.

The laws take time, need to be tested in courts and are generally not as effective.

If you're constantly under threat of losing your entire income stream and there's nothing you can do to prevent that (because the only way to prevent piracy of digital content is to ban the internet) it's a pretty decent motivator to do the right thing.