I agree. NFTs are currently useless, but interoperability would change that. One of the big drawbacks of current DRM tools is that they're centralized within a single vendor. If there are multiple vendors for a digital item, you can't carry your ownership of that item between vendors.
There are a few existing solutions to this. Movies Anywhere[0] consolidates your video purchases across 8 vendors[1]. It mostly works ok. The problem is that I still have to trust those vendors, and this industry consortia, to manage the property rights for me. I can't prove that I own a particular movie outside of that ecosystem. I want to download the movie and transcode it for personal use, and prove that I legally own the right to that movie file outside of their system. If I own a copy of the movie, I should be able to take that copy of the movie anywhere.
Music is similar. Remember a few years ago when a bunch of music services added "upload your offline library and we'll make it available on the cloud" services? That was basically using the files on your computer (ostensibly obtained by ripping a physical CD you bought at a store) as a DRM key to unlock new features within the platform. Personally, I got burned by this when Google Music got shut down and took my uploaded music with it (backups, yes). It would make a lot more sense to have a wallet of licenses that I could present to any of these services.
Finally, the BIG thing with interoperability is freedom of exchange. I want to be able to sell my digital stuff to somebody else. Or lend it to them. Or present it to a new vendor / media player / device.
MOST importantly, I want to use the media myself wherever and for whatever I want, without worrying that I'm somehow breaking the law. I want to make mashups. I want to self-host. I want to dump everything in a new hosted service and see how it works. And I want to do all that knowing that it's all above board and the creator's are compensated fairly for their work. The current system works for Disney. I'm much more interested in the artisan digital economy.
NFTs do not deliver on this vision today. Additional technology is needed. Content-addressed, distributed storage like IPFS would be helpful. We might even need opinionated regulation to get the big players on board. Just look at the difference between electronic bank transfers in Europe and the state of US electronic medical records to see what I'm talking about.
[0] https://moviesanywhere.com/welcome
[1] AppleTV/iTunes, Amazon Prime Video, Fandango/Vudu, Google Play/YouTube, Microsoft Movies & TV, Xfinity, Verizon and DirectTV