Lots of Amazon music, in addition to Prime usage, is probably used with Alexa as well as that is the default music player on Alexa/Echo. Just like Siri/Homepod

Lots of Amazon music, in addition to Prime usage, is probably used with Alexa as well as that is the default music player on Alexa/Echo. Just like Siri/Homepod uses Apple Music and "Hey Google" / Google Home/Helper uses Google Play/Youtube music.