What will happen is, it will occupy some space on your device. So, when you clear App Data, it not only clears the Cache but also resets the application, meaning you’ll have more space in storage. But you will have to sign in again on Netflix.
Clear the cache Cached data can save a little time (and mobile data), but the files stored in app caches are for convenience and are not strictly necessary. If you need to clear up space on your phone quickly, the app cache is the first place you should look.