My phone makes phone calls and browses the Internet. There are things that can do multiple things.
The use case is not different. There is already music on YouTube. I rarely watch YouTube but I listen to it a lot. You’re not actually upset about the new app, you’re excited to shit on a company with harmful practices and you’re grasping at any argument you can find.
No, I use both YouTube and YouTube music and they need different UIs and ways of navigating. While you could cram all of YouTube musics UI into a subsection of YouTube, it really doesn’t make sense to do so. I’m not just shitting on Google just because, I’m saying that the needs of music listening and YouTube video watching are different for many people.
Honestly sounds like you don’t even need youtube, just YouTube music if all you ever use it for is listening.