Unlike Alexa and Google Assistant, Siri has been limited to Apple devices since its introduction nearly a decade ago. However, the situation has changed this year-Apple just announced that third-party devices will be able to use Siri as part of the company's HomeKid system update. Apple showed someone calling Siri on the Ecobee thermostat. But according to a short demonstration, it sounds like these third-party devices will not be mature devices that run Siri on their own. Instead, it will relay the command to the HomePod mini, and then the HomePod mini will send the request. Apple specifically stated that third-party companies will not be able to see these Siri commands.
It is not clear whether other devices, such as Apple TV, can also act as a Siri hub. We have to imagine that the original, now discontinued HomePod will also be able to link to third-party Siri devices, but we must wait until Apple’s activities are over and learn more about the rules here.