YT-DLP is Being Treated as a Piracy Tool By The IFPI

Can it download any of those paid movies? That might be the only thing that makes sense

I mean technically speaking unless you have permission of the copyright owner to download their video any tool you use to download (almost) any YouTube video would be a piracy tool.

Your web browser necessarily has to download a YouTube video in order to display it to you. It just doesn’t provide an easy way for that data to be more than ephemeral.

Going to YouTube and having your browser download the video so you can watch it would be an approved way to download the video, making further copies of it more than likely not.