As long as I can't stream the audio to multiple airplay devices then it is DOA for me. I can't reason why Apple hasn't been clear about why the airplay option is unavailable for beats1. Sure, I can stream audio (and all my computer sounds) through a single airplay device, but that is limiting as compared to all the other radio stations available through Apple Music.
And while my music tastes are pretty broad, just about every time I decide to give beats 1 yet another go, I find the music to be the same old hip-hop/rap. It would be great if they do add more live radio stations that cater to different music tastes.
Out of curiosity, why do you want to be able to stream to multiple devices?