I understand your opinion. You like it the way it is and that’s fine. I think the new UI is more in the way of an immersive experience. Google released a concept for its Play Music service back in 2014/2015 that showed the potential of its Material Design guidelines. The player inherited colors from the currently playing songs artwork and used those colors to change the theme of the player to match.
Google never implemented this design which is too bad, I think their Play Music app now is downright terrible. But I think Spotify could use some of these subtle touches to improve on their UI and set it apart from the competition. All music apps work the same way and for the large part look the same as well.
Tldr; Why not be creative, break the traditional player UI and come up with something fresh and attractive to its users?
I also notice the new UI, worst thing is, I can't seem to edit a playlist (I do that even on pre-set playlist of Spotify), or can it be done in some way? Also, I notify the "behind lyrics" is not available anymore... so many changes and I seem to getting less out of the app now