Just what I was looking for!

Ive been trying to figure out how to get Siri to play music via voice activation for months, with no luck. This app is the solution! Although you have to press the speaker button, you dont have to search through playlists or the Spotify archives to play the song that youre in the mood for! Side note: Only works for Spotify Premium users.

real_soul_survivor33 about Joy - Voice Controlled Music Assistant, v2.0