Spotify recently made a major change for Free users without announcing it. Free is the free to use subscription of the music streaming service, where you will hear commercials between songs.
Spotify Free without Google Cast
An update has meant that Spotify Free users can no longer cast music to speakers and smart displays with the Google Assistant on-board. The function can still be seen in the app. But when free users want to send their music to smart speakers or screens, they will see a new message on the screen. That message states that only Premium users can access that functionality.
It doesn’t matter whether you play music or turn on a podcast. In both cases, keep in mind that the feature will only work for owners of a Premium subscription.
This no longer works from the mobile app, but you can bypass the restriction by linking your Spotify Free account to your Google account via Google Home. You can then ask the Google Assistant if it wants to set up a specific playlist or podcast via Spotify. The question is how long this detour will last. This may be blocked in the future.
If you want to continue to use Spotify the old-fashioned way, you need to take out a subscription. That will cost you at least 9.99 euros per month. Spotify has not yet responded to questions from the press. On the explanation pages we can also find nothing about the change.