Downloading the Crunchyroll copyright from places other than the official app stores (like Google Play Store or Apple App Store) can be a bit risky, kind of like accepting candy from a stranger.
These unofficial copyright files might have been changed without you knowing. They could contain bad stuff like viruses or software that can mess up your phone or even try to steal your information. It's always safer to get your apps from the official stores because they have security checks to try and make sure the apps are safe.