It seems to be the case that Xbox wants to get Game Pass on every platform possible, so why not get it on Amazon Alexa? While you can't play the games that way, you can tell Alexa to queue titles for download.
Beginning next week, Xbox Game Pass subscribers who link their accounts to their Amazon Alexa-enabled devices will be able to command Alexa to begin downloading any of the 200+ games currently in Xbox Game Pass. This includes not just the at-home Alexa most are familiar with, but also Echo Buds, in the car with Echo Auto, and more.
This update comes just a few months after an Alexa app joined Xbox Series X|S consoles which allows for more voice-controlled functionality of players' consoles. The Alexa/Game Pass integration can be used in a limited capacity without even linking accounts as well. Users can ask Alexa about what's new to Game Pass, leaving the library soon, or popular and trending right now.
It's expected that sometime this year Xbox will also reveal a Smart TV app for Game Pass, which will allow users to access the Game Pass library via the cloud just as Android, and soon iOS, users can do on phones and tablets. It all points to Phil Spencer's words from March when he spoke of "platforms where Game Pass exists" when referring to where players can find future Bethesda titles.
It's not the same as saying "on Xbox and PC" because in the future, "platforms where Game Pass exists" may mean very different things - perhaps even Nintendo Switch.