The content owner could still request your information from the VPN provider and the VPN provider might provide it (even if they say they won't). I think the main benefit is that there are so many individuals torrenting copyrighted material that aren't using VPNs that it means you aren't the "low hanging fruit" so you're considered not worth the effort by the content owners.
Yes, but there is a big difference between "this provider might be lying about not storing traffic, and they also might give the data to someone" and "this ISP is 100% storing traffic and routinely gives that data to others."
