Before iOS 13, there was no way to ask Siri to play something on Spotify or any other music app. Then came the update that allowed us to command Siri by saying “play xyzsong on Spotify”. Now, with iOS Beta 14.5, users can set a default music app for Siri and just ask it play a song on whatever platform you prefer.
Users in Beta that asked Siri to play a song for the first time were given a list of music streaming apps to choose from. After selecting their choice, Siri would play from that app only without having to mention which platform.
The feature is in beta right now and there’s no word of whether or not it will make up in the final iOS 14.5 release.