couldn't you do approximately the same thing if your phone is already bluetooth connected to the stereo? in the case of the Amazon device, Alexa does your bidding, but with the phone Siri should be able to serve up similar content, if you are subscribed to the source of the music.

I use my phone in conjunction with wireless air pods to listen to music while I ride my bicycle. Hands free commands to call up, start, stop or cancel music from Spotify or other music app on the phone really makes biking a lot more fun. Disclaimer: some music platforms have limited feature sets with Siri