I've been an Apple Music subscriber for 2 years, and so far I haven't made any smart playlists. Today I decided to try it and didn't have the experience I was hoping for. What I was hoping for was that if I just like a song I come across, it will automatically be part of the designated playlist, and when I downloaded all of my smart playlists, it was automatically downloaded. In the real world, I should first add the song to my library, then download and love it to make the scenario I hoped to happen. Common playlists, on the other hand, are a different story. If I download a personal playlist and just add some songs I come across, they are automatically downloaded without having to add them to my library and download them. TL; DR: Smart playlists don't work like magic to me.