Hi Jeff.
Yes, with bluetooth is possible, I know. But with this bluetooth method, I can´t "free" my phone, it is tied to the Echo device. What I would like to do is that once I looked and found my playlist in the iPhone and begin to play, pass the control and the playing to the Echo. Then I can switch off my phone if I want to. The playlist is now playing on the Echo and then say, for example "Alexa, pause". With spotify and Amazon Music it is posible to do so.
Currently only with apple music, If I want to play a playlist on Alexa I must know the playlist name (for example My Last Summer Songs) and say "Alexa play My last summer songs playlist from Apple Music". If I have 50 playlists, it is impossible to remember all playlist's names. With Spotify or Amazon Music APPS, I can, with the iPhone, browse comfortably trhough all my playlists, choose one, press PLAY, then send the playing to the Echo. Then turn off my phone if I want, or make a call or view YouTube. The music is playing in the Echo and I can pause, next, etc with my voice and listen to all Echos devices in my home. The playing and the control is now on the Echo. Is Apple Music able to do this? Spotify & Amazon Music apps can. I really want to switch to Apple Music and leave Spotify, but I need this feature.