I just downloaded and have been loving this. It loads pretty quickly, navigation is intuitive, and I'll finally stop forgetting that Nebula exists because it'll all be in my one big subscription feed.
Since I'm new to moving over to open source, I want to ask the veterans: is this as incredible as it seems right now, or is there something I'm missing?
I think the main point is, this makes it unavailable in F-Droid and everyone else unable to build upon, use or adapt it for their own use-cases except for the specific ones outlined by FUTO. It's source-available software. Not free software. And it has other downsides, too. Once YouTube starts cracking down on third-party apps and the companies behind it, it's gone for good. yt-dl has demonstrated free software offers more resilience in those cases.
And I'd argue it's ineffective. Having a license forbid malicious use will only stop the honest people from using it. The bad players will probably not care. But that's debatable.